"I want to tell you that your fact sheet on the [Missile Technology Control Regime] is very well done and useful for me when I have to speak on MTCR issues."

– Amb. Thomas Hajnoczi
Chair, MTCR
May 19, 2021

A New Argument for Nuclear Arms Control: Climate Change

November 2023
By Kenneth C. Brill

There is no shortage of reasons to be pessimistic about the future of nuclear arms control.

Smoke and flames rise from a mountain during a wildfire in Chongqing, China in 2022. Every nuclear- and non-nuclear-weapon state will confront the impacts of climate change in the years to come. (Photo by VCG/VCG via Getty Images)Relations among the major nuclear powers have soured. Russian President Vladimir Putin has made veiled nuclear threats related to Russia’s full-scale war on Ukraine and stopped Russia’s implementation of the New Strategic Arms Reduction Treaty. China plans to increase its nuclear weapons stockpile and has rejected U.S. efforts to engage on strategic nuclear issues.1 In the United States, a rising chorus argues that nuclear arms control is over and that the U.S. nuclear stockpile should be increased, not just modernized.2 Meanwhile, states such as India, North Korea, and Pakistan are increasing their nuclear stockpiles.3

Nonetheless, another increasingly evident global threat provides compelling reasons for nuclear-armed nations to assess that a renewed push for nuclear arms control is very much in their long-term security interests. That threat is the impact of climate change on the natural world. The increasing number, intensity, and variety of natural disasters across the globe in recent years have demonstrated the growing danger to all states, whether nuclear armed or not. The cascading impacts of climate change on the natural world are no longer simply a concern of environmentalists or insurance companies; they are becoming a national and global security challenge that will intensify for decades to come. Dealing with this new threat to prosperity and stability will require developing an international strategic balance that recognizes that weapons of war are not the best defense against what will be the most sustained threats of the 21st century and beyond.

Reviving arms control diplomacy will be essential to achieving this new strategic balance. The goals of that diplomacy would be to rebuild or, in some cases, establish confidence among nuclear-armed states; reinforce constructive existing nuclear norms; sharply reduce the number of nuclear weapons; and free up resources to deal with the national and global consequences of climate change.

Facing a Common Threat

Nuclear arms control diplomacy was invented at the height of the Cold War when distrust between nuclear powers was deep, communications limited, and the threat of conflict a daily reality. Every U.S. president from Dwight Eisenhower until Donald Trump undertook diplomatic initiatives that produced arms control agreements. As a result, the combined U.S. and Russian stockpiles were reduced from some 60,000 weapons in the mid-1980s to a little more than 12,000 in 2020.4 In addition, constructive new norms—no use of nuclear weapons on the battlefield and no nuclear weapons testing—were established and are still holding.5

Despite the contentious post-cold war geopolitical situation, arms control diplomacy succeeded because the parties involved had shared interests. That perception of shared interest seems elusive now, given stepped up Chinese-U.S. competition over shaping the international order, Putin’s break with the West, and India’s ongoing strains with Pakistan and China. Even so, every nuclear- and non-nuclear-weapon state faces a common threat in the coming decades and beyond, namely the cascading impacts of climate change on the natural world within and outside their borders. That common threat is an opportunity for developing common ground on arms control.

Money for Nothing…or for Something?

Nuclear weapons are expensive to build, maintain, and modernize. According to one estimate, in 2021 the world’s nine nuclear-weapon states spent $82.4 billion on their nuclear weapons programs, with the United States investing the most, followed by China and Russia.6 The estimated cost for the U.S. nuclear stockpile modernization program over its planned 30-year life span is $1.5 trillion.7

In January 2022, China, France, Russia, the United Kingdom, and the United States issued a statement reiterating what U.S. President Ronald Reagan and Soviet leader Mikhail Gorbachev vowed in 1985, that a nuclear war can never be won and must never be fought. They also committed to the ultimate goal of a world without nuclear weapons with undiminished security for all.8 Assuming that those commitments are serious, vast sums of money are being spent on weapons that none of the nuclear-weapon states expects to use, even as they insist that possessing nuclear weapons is necessary in today’s geopolitical environment. Climate change, however, will upset the notion of what constitutes the most pressing national threats.

High temperatures, droughts, and intense rain events that produce inland flooding of arable land will reduce food production and increase food prices. Rising sea levels, more intense storms, and associated flooding will destroy coastal infrastructure, undermining the capacity of coastal cities to support their populations. Cities and infrastructure in many countries also will be affected by intense storms that result in inland flooding. High temperatures and droughts will reduce the national GDP of many states and make some areas unable to support current populations.9

The World Bank reports that these factors could force some 216 million people to be displaced within their own countries by 2050, with internal displacement “hotspots” occurring as early as 2030.10 A European think tank foresees an even more dire situation, estimating that some 1 billion people could be displaced by 2050 due to climate change, conflict, and civil unrest. Some, possibly many, of those internally displaced people subsequently will seek to migrate to other countries.11 A White House study assessed that climate-related migration has potentially significant negative implications for international security, instability, conflict, and geopolitics.12

Dealing with climate change will be expensive. A 2018 report assessed the then net present value of projected damages globally by 2100 from an increase in global temperatures of 1.5 degrees Celsius at $54 trillion or $69 trillion from an increase of 2.0 degrees.13 Meanwhile, Swiss Re, a leading global reinsurer, estimates that if greenhouse gas emissions are not reduced quickly, climate change is likely to cut total global economic output by some 11-14 percent, or up to $23 trillion.14 The International Energy Agency estimates it will cost $5 trillion in annual new energy investments by 2030 to meet the Paris Agreement goal of holding the increase in global temperatures to 1.5 degrees Celsius.15 The UN Environment Programme estimates that climate change adaptation costs faced by developing countries alone will be $140-300 billion annually by 2030 and $280-500 billion by 2050.

Climate change will not just hurt developing countries; nuclear-weapon states also will feel the pain. For example, Swiss Re assesses that China’s economy has the highest climate risk of any major economy, noting that its GDP could be reduced by as much as 6.6 percent by 2048 even if global temperatures increase only 1.5 degrees Celsius or by 18 percent if they rise by 2.6 degrees Celsius.16 The World Bank agrees, noting the vulnerability of China’s coastal cities, such as Shanghai and Guangzhou, to rising sea levels and its agricultural regions to drought.17 Among other nuclear-armed states, the U.S. intelligence community assesses India, North Korea, and Pakistan to be highly vulnerable to the cascading impacts of climate change.18

Climate change has economic and financial effects on the United States as well. Weather and climate disasters from 2016 to 2022 cost the country more than $1 trillion in storm and related damages, and 2023 already has set a record for the number of U.S. natural disasters producing more than $1 billion in costs.19 More broadly, a 2018 study estimated that U.S. GDP could be cut 10 percent by 2100 with a business-as-usual approach to climate change.20 Meanwhile, the White House reports that a failure to act on climate change could reduce revenue to the U.S. Department of the Treasury by $2 trillion per year, even as demands for climate-related expenditures, such as disaster relief and crop insurance payments, increase.21

Developed nations will be under increasing pressure to financially support developing countries in dealing with the effects of climate change. The need in developed countries to reduce transnational climate migration from developing countries will be a major incentive to do so. The growing political, economic, and humanitarian ramifications of climate change-related transnational migration are already evident, for example, along the southern U.S. border, in the flow of migrants across the Mediterranean to Europe, and in the movement of Bangladeshis into India. If not addressed, this climate-related flow of human misery only will increase and become more unsettling in the coming decades.

A Forever Timescale

The fiscal consequences of climate change not only will be substantial for developed and developing nations, they also will be enduring. Emitted carbon dioxide remains in the atmosphere for 300 to 1,000 years.22 Dramatically reducing greenhouse gas emissions and then dealing with the impact of these emissions on the natural world, including by removing them from the atmosphere, will therefore be the work of and fiscal burden on many generations. This means climate change-related expenditures and economic costs will become a substantial factor for most countries essentially in perpetuity.

Geopolitics inevitably will be affected by climate changes. Polar melting will create opportunities for jockeying among polar nations and others over new sea-lanes and some newly exposed territory, but that is more likely to be transitory than world changing. What comprises national power in a time of a transforming natural world, however, is likely to be different than what it was earlier. In today’s geopolitics, nuclear weapons represent power and status. Proponents of nuclear weapons cite their value in deterring attacks from other nations. Yet, nuclear weapons will not deter the growing threats to national stability and power from sea level rise, drought, or rising temperatures that reduce national economic output. They also will not deter the displacement of domestic populations or the stresses produced by transnational migration.

This submarine is part of China’s 094A Jin-class of nuclear sea-based capabilities, which is equipped to carry up to 12 sea-launched ballistic missiles. China, Russia and the United States are all investing heavily in their nuclear weapons arsenals but experts say their national GDPs will decline if the climate change threat is not addressed. (Photo by Mark Schiefelbein/AFP via Getty Images)In the future, power is likely to accrue to states that successfully sustain their economies and national cohesion despite the pressures created by a mutating natural world. This will take considerable, sustained investments in climate change mitigation, adaptation, and resilience. These investments will dwarf what is being done today and will strain national climate-impaired fiscal capacities.

As a result, nuclear weapons increasingly will be neither a status symbol, nor relevant to the most urgent threats facing nuclear- and non-nuclear-weapon countries, but instead become an opportunity cost. That is, money spent on weapons that no one wants or has a plausible reason to use is money that cannot be used to address climate-related threats to national prosperity, stability, and security, which will be tangible and domestically urgent.

Mutually Assured Destruction or a Mutually Assured Future?

Despite fiscal pressures and growing political demands to address climate change-related challenges, particularly at home, no nuclear-armed state will unilaterally reduce its nuclear stockpile. Nuclear arms control diplomacy needs to be revived to help nuclear-armed nations and the global community as a whole transition from mutually assured destruction strategies to a strategic balance that addresses climate change impacts and promotes a mutually assured future.

Arms control diplomacy in a time of climate change must be different from the Cold War variety. Although the nuclear Nonproliferation Treaty and the Chemical Weapons Convention are global agreements, the bulk of the arms control instruments were negotiated on a bilateral basis between the Soviet Union/Russia and the United States. With the current roster of 10 nuclear- or near-nuclear-armed states, the time for bilateral arms control diplomacy is over.

Yet, the unsuccessful U.S. efforts to engage China in nuclear arms discussions and the failed multilateral efforts to persuade North Korea to abandon its nuclear weapons program demonstrate the challenges of moving beyond the Russian-U.S. construct of nuclear negotiations. One of the difficulties is that, despite sizeable reductions in the past, there is still a large gap between the Russian and U.S. nuclear stockpiles and everyone else. Another challenge is the deep distrust and tensions among most of the nuclear- or near-nuclear-armed states.

A Russian Iskander-M dual-capable missile system is launched in 2018. Arms Control Today contributor Kenneth C. Brill writes that nuclear weapons will not deter the growing threats from climate change. (Photo by Mil.ru/Wikimedia Commons)Reviving nuclear arms control and making it relevant for the climate change age will require leadership and creativity; it will also take time. Moscow and Washington took decades to reach significant bilateral nuclear arms control agreements. Negotiations involving even more nations with significantly different weapons programs will be even more complex and time consuming. Nonetheless, climate change impacts are growing; and a status quo approach will become increasingly untenable for nuclear-armed nations and others, so it is time to get started with thinking about how to advance arms control in a time of climate change.

Despite its polarized domestic politics, strains with China and Russia, and recent quiescence on arms control, the United States is best placed to initiate new thinking and action on nuclear arms control. It has experience in developing and moving forward with nuclear-related initiatives, such as President Barack Obama’s nuclear security summits, and it is allied with or has constructive relations with five other nuclear-armed states (France, India, Israel, Pakistan, and the UK).

The first step in the diplomatic process would be for the United States to commit internally to pursuing nuclear arms control talks with other nuclear-weapon powers to reduce the threat of the use of nuclear weapons and allow greater focus on dealing sustainably with the impacts of climate change at home and elsewhere. Such an initiative would take years to develop and produce results, so bipartisan support would be essential, if challenging to obtain. Toward this end, the United States should explore the subject early on with its two NATO nuclear-weapon allies, France and the UK, with the goal of building a unified core to move the process forward procedurally and substantively.

Although negotiations eventually should focus on numbers of weapons, beginning with numbers would be unproductive, given existing tensions among various nuclear-armed states and the differences in their nuclear weapons programs. In his final book, the arms control scholar and practitioner Michael Krepon sensibly suggested that a multilateral arms control negotiation might gain traction by focusing on reinforcing three nuclear norms: no use of nuclear weapons in a conflict, no testing of nuclear weapons, and no proliferation of nuclear weapons to non-nuclear-armed states.23

The initial efforts at developing a multilateral nuclear arms control negotiation should focus on the eight most developed of the 10 nuclear-armed and near-nuclear-armed states, namely China, France, India, Israel, Pakistan, the UK, and the United States. Ideally, after gaining French and UK support, the United States would engage each of the remaining states on their concerns and ideas for advancing a process that would strengthen confidence among the nuclear-armed states and encourage collaboration on ensuring that nuclear weapons materials remain secure, despite the impacts of climate change.

New arms control initiatives will be needed so that funds now directed at nuclear weapons can be invested in projects dealing with the threat of climate change. In August, Joint Forces Training Base in Los Alamitos, Calif. inaugurated a project intended to increase energy resilience for the base and Southern California by adding locally generated carbon-free renewable electricity to the grid.  (Photo by Frederic J. Brown/AFP via Getty Images)If the initial U.S.-led bilateral consultations show promise, a meeting should be convened of the eight states consulted or some sub-group to explore how much further the process could go. Because the perception of U.S. leadership on this issue would be anathema to at least two nuclear-armed states, a neutral convener would be needed to arrange group meetings. The logical choice is the International Atomic Energy Agency, where all eight states are members. It could convene low-key meetings of the group and keep initial discussions informal and out of the limelight until all parties concur that there is something to be gained by this process. As the process proceeds, the states gain confidence with one another, and the impacts of climate change become increasingly evident, participants can expand their ambitions and move toward negotiating reduced numbers of nuclear weapons.

Once there is engagement and positive momentum on making nuclear arms reductions among the eight, which could take years to achieve, it would be useful for some of the eight to reach out to North Korea and possibly to Iran to invite them into the process.

Problems Create Opportunities

Given the state of international affairs, particularly the ongoing violence in Ukraine and the renewed violence in the Middle East, the idea of a nuclear arms control initiative may sound absurd. Yet, a changing climate will alter the natural world dramatically and, in so doing, fundamentally change what counts as national and global security. This transforming world requires a new strategic balance between nuclear-armed nations, as well as between all nations and the natural world. Robust nuclear arms control diplomacy can help establish that new strategic balance between nations, significantly reduce or eliminate nuclear weapons, and free up resources needed to deal with the daunting financial challenges of restoring balance with the natural world.

The road to positive results for this new arms control diplomacy will be long and challenging, requiring unprecedented cooperation and collaboration between nations, as well as between those officials managing security issues and those dealing with climate-related issues. Although arms control diplomacy was useful in the 20th century, it is essential for the 21st century and beyond. It is time to get started on it.



1. Shannon Bugos, “Pentagon Sees Faster Chinese Nuclear Expansion,” Arms Control Today, December 2021, p. 26.

2. Bryant Harris, “U.S. Nuclear Commander Warns of Deterrence ‘Crisis’ Against Russia and China,” Defense News, May 4, 2022; Patty-Jane Geller, “U.S. Nuclear Weapons,” in 2023 Index of U.S. Military Strength, ed. Dakota L. Wood (Washington: The Heritage Foundation, 2023), pp. 481-506, https://www.heritage.org/sites
; Chris Gordon, “U.S. Should Consider Expanding Nuclear Arsenal to Cope With China and Russia, Study Says,” Air and Space Forces Magazine, March 31, 2023, https://www.airandspaceforces.com/us-consider-expanding-nuclear-arsenal-china-russia/.

3. Stockholm International Peace Research Institute, “States Invest in Nuclear Arsenals as Geopolitical Relations Deteriorate—New SIPRI Yearbook Out Now,” June 12, 2023, https://www.sipri.org/media/press-release/2023/states-invest-nuclear-arsenals-geopolitical-relations-deteriorate-new-sipri-yearbook-out-now.

4. “Historical Nuclear Weapons Stockpiles and Nuclear Tests by Country,” Wikipedia, n.d., https://en.wikipedia.org/wiki/Historical_nuclear_weapons_stockpiles_and_nuclear_tests_by_country (accessed October 18, 2023).

5. Michael Krepon, Winning and Losing the Nuclear Peace: The Rise, Demise, and Revival of Arms Control (Stanford, CA: Stanford University Press, 2021), p. 9.

6. Giulia Carbonara, “U.S. Nuclear Weapons Spending Compared to China and Russia,” Newsweek, June 14, 2022, https://www.newsweek.com/us-nuclear-weapons-spending-compared-china-russia-1715542.

7. Kingston Reif, “The Trillion (and a Half) Dollar Triad?” Arms Control Association Issue Brief, Vol. 9, No. 6 (August 18, 2017), https://www.armscontrol.org/issue-briefs/2017-08/trillion-half-dollar-triad.

8. The European Leadership Network, “The Reagan-Gorbachev Statement: Background,” November 17, 2021, https://www.europeanleadershipnetwork.org/commentary/the-reagan-gorbachev-statement-background/; The White House, “Joint Statement of the Leaders of the Five Nuclear-Weapon States on Preventing Nuclear War and Avoiding Arms Races,” January 3, 2022, https://www.whitehouse.gov/briefing-room/statements

9. The Intergovernmental Panel on Climate Change, “Summary for Policymakers,” 2018, https://www.ipcc.ch/site/assets/uploads/sites/2/2022/06/SPM_version_report_LR.pdf.

10. The World Bank, “Climate Change,” May 12, 2023, https://www.worldbank.org/en/topic/climatechange/overview.

11. Institute for Economics & Peace, “Over One Billion People at Threat of Being Displaced by 2050 Due to Environmental Change, Conflict and Civil Unrest,” September 9, 2020, https://www.economicsandpeace.org/wp-content/uploads/2020/09/Ecological-Threat-Register-Press-Release-27.08-FINAL.pdf.

12. The White House, “Report on the Impact of Climate Change on Migration,” October 2021, https://www.whitehouse.gov/wp-content/uploads/2021/10/Report-on-the-Impact-of-Climate-Change-on-Migration.pdf.

13. “Risks Associated With Global Warming of 1.5ºC or 2ºC, Tyndall Briefing Note, May 2018, https://tyndall.ac.uk/wp-content/uploads/2021/11/briefing_note_risks_warren_r1-1.pdf.

14. Christopher Flavelle, “Climate Change Could Cut World Economy by $23 Trillion in 2050, Insurance Giant Warns,” The New York Times, April 22, 2021.

15. International Energy Agency, “Net Zero by 2050: A Roadmap for the Global Energy Sector,” May 2021, https://iea.blob.core.windows.net/assets/7ebafc81-74ed-412b-9c60-5cc32c8396e4/NetZeroby2050-ARoadmapfortheGlobalEnergySector-SummaryforPolicyMakers_CORR.pdf.

16. Swiss Re Institute, “The Economics of Climate Change,” April 22, 2021.

17. The World Bank, “China Country Climate and Development Report,” October 2022, https://www.worldbank.org/en/country/china/publication/china-country-climate-and-development-report; Dharisha Mirando et al., “CWR City Factsheets: At-a-Glance Coastal Threat Assessment for 20 APAC Cities,” November 2020, pp. 9-10, 25-26, https://www.chinawaterrisk.org/wp-content/uploads/2020/11/CWR_APACCT_20_Index_CityFactsheets.pdf.

18. U.S. National Intelligence Council, “National Intelligence Estimate: Climate Change and International Responses Increasing Challenges to US National Security Through 2040,” NIC-NIE-2021-10030-A, n.d., https://www.dni.gov/files/ODNI/documents/assessments/NIE_Climate_Change_and_National_Security.pdf.

19. National Centers for Environmental Information, U.S. National Oceanic and Atmospheric Administration, “Time Series,” October 23, 2023, https://www.ncei.noaa.gov/access/billions/time-series.

20. Caroline McMahan, “The Rising Costs of Global Warming,” Michigan Journal of Economics, March 13, 2021, https://sites.lsa.umich.edu/mje/2021/03/13/the-rising-costs-of-global-warming/.

21. Candace Vahlsing and Danny Yagan, “Quantifying Risks to the Federal Budget From Climate Change,” April 4, 2022, https://www.whitehouse.gov/omb/briefing-room/2022/04/04/quantifying-risks-to-the-federal-budget-from-climate-change/.

22. Alan Buis, “The Atmosphere: Getting a Handle on Carbon Dioxide,” October 9, 2019, https://climate.nasa.gov/news/2915/the-atmosphere-getting-a-handle-on-carbon-dioxide/.

23. Krepon, Winning and Losing the Nuclear Peace, pp. 523-525.

Kenneth C. Brill is a former acting U.S. assistant secretary of state for the Bureau of Oceans and International Environmental and Scientific Affairs, a former U.S. ambassador to the International Atomic Energy Agency, and founding director of the U.S. National Counterproliferation Center.

Dealing with this new threat to prosperity and stability will require a recognition that weapons of war are not the best defense against the most sustained threats of the 21st century and beyond. 

Reducing Tensions Over Nuclear Testing at Very Low Yield

November 2023
By Julien de Troullioud de Lanversin, Christopher Fichtlscherer, and Frank N. von Hippel

The U1a Complex is an underground laboratory at the U.S. Nevada National Security Sites where scientists conduct subcritical and physics experiments to obtain technical information about the U.S. nuclear weapons stockpile. (Photo courtesy of Nevada National Security Sites)Twenty-three years after Russia ratified the Comprehensive Test Ban Treaty (CTBT), Moscow is “unratifying” but not unsigning the pact as a by-product of its war on Ukraine and related tensions with the United States.1

Such a move would contradict Russia’s previously stated commitments to help bring the CTBT into force and is another body blow to the embattled international arms control regime.

Although China and the United States have not ratified the treaty, they have signed it, effectively abided by it, and with Russia and several other states, have anchored a de facto moratorium on nuclear testing. Recent accusations made by the United States, however, have cast doubts on whether Russia and perhaps China are still adhering to their moratoriums for certain types of tests at very low yields.

With increasing nuclear tensions between great powers, these suspicions could lead nuclear-weapon states to abandon their moratoriums and resume full-scale nuclear weapons tests. It is therefore imperative that they discuss a new transparency and verification regime for very low-yield tests.

China most likely is waiting for the United States to ratify the treaty, but without a major educational and lobbying campaign backed by the White House, most Republican senators could be expected to revert to the position of their caucus, which voted against CTBT ratification in 1999.2 For the CTBT to come into force, China, Russia, the United States, and six other specific countries still must ratify it.3

According to the Vienna Convention on the Law of Treaties, however, treaty signatures, unless they are withdrawn officially, obligate countries to comply with the treaty.4 All states other than North Korea have observed a testing moratorium since 1998, and North Korea has not tested since 2017.

In the absence of muffling in an enormous, mined cavity, the International Monitoring System of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) can detect nuclear tests of a yield of about 100 tons of TNT equivalent.5 That amount is less than 1 percent of the yield of the bomb dropped on Hiroshima. National and civilian seismic networks provide additional, more sensitive capabilities near former nuclear test sites. The CTBT, however, requires parties “not to carry out any nuclear weapon test explosion or any other nuclear explosion.”6 It is a “zero yield” treaty.

In 2016, China, France, Russia, the United Kingdom, and the United States issued a joint statement asserting “that a nuclear-weapon test explosion or any other nuclear explosion would defeat the object and purpose of the CTBT. ”7 According to the U.S. Department of State, the United States and the other governments participating in the CTBT negotiations agreed that the treaty “prohibits all nuclear explosions that produce a self-sustaining, supercritical fission chain reaction of any kind.”8 A fission chain reaction is called supercritical when it is exponentially growing and subcritical when it dies out. This interpretation of zero yield is commonly referenced as the U.S. zero yield standard.

An article-by-article analysis of the treaty submitted to the U.S. Congress by the Clinton administration in 1997 listed some explosive experiments that the U.S. nuclear weapons design laboratories would be allowed to conduct under the treaty. These include inertial confinement fusion experiments such as the laser-driven implosions of deuterium and tritium being carried out at the Lawrence Livermore National Laboratory’s National Ignition Facility and subcritical experiments with plutonium conducted underground in Nevada by the Livermore and Los Alamos national laboratories.9

Russian Defense Minister Sergei Shoigu (R, front) visited the Russian nuclear weapons test site Novaya Zemlya in August, adding to Russian-U.S. tensions over the testing issue. (Photo by the Russian Defense Ministry with location confirmed by The Middlebury Institute of International Studies)The U.S. government claims that China and Russia may be violating the U.S. interpretation of the treaty by carrying out supercritical tests in steel containment vessels underground. More than six decades ago, during the 1958-1961 test moratorium and the associated negotiations that ultimately produced the Partial Test Ban Treaty, the United States carried out very low-yield supercritical tests, which at that time were referenced as “hydronuclear” tests. The purpose of these experiments was to determine whether the fission “primaries” of some warheads recently added to the U.S. nuclear stockpile were “one-point safe.” A nuclear warhead is said to be one-point safe when no significant nuclear yield can be produced if the explosive around the plutonium pit is detonated at a single point by, for example, a bullet.

In these experiments, the amount of plutonium in the pit was reduced to a level where the pit was definitely one-point safe and then the plutonium was added back bit by bit. At each step, the explosive around the pit was detonated at what was believed to be its most sensitive point until there was a measurable fission yield or the one-point safety of the primary had been established. The increments of plutonium were kept small enough so that the fission energy released would be less than that released by one pound (about 0.5 kilograms) of TNT.10 The Soviet Union also conducted such tests, in large “Kolba” vessels designed to contain explosions with total energy yields (chemical explosive plus fission) up to 50 kilograms of TNT.11 Such low-yield tests would not be detected by the CTBTO off-site monitoring instruments.

There is little interest in hydronuclear experiments in the United States today. A 2012 discussion of hydronuclear testing by the U.S. National Academy of Sciences could not “identify any significant advantage that could accrue to a state testing at…very low levels (<1 ton [TNT equivalent]).”12 The nuclear weapons laboratories are confident in the one-point safety of U.S. nuclear warheads. The focus of the laboratories is instead on carrying out subcritical nuclear tests to verify that the plutonium metal behaves as required when imploded.

In a subcritical test, an assembly of plutonium is imploded inside a containment vessel, and neutrons are introduced into the imploded mass to initiate a fission chain reaction. Because the mass remains subcritical, the chain reaction dies away. With current technical limitations on how many initiating neutrons can be introduced into the imploded plutonium mass, planned U.S. subcritical tests would generate about 10 billion fissions,13 which would release about 0.3 joules of energy, roughly equal to what would be released by the detonation of about 0.1 milligrams of TNT.

The measurement equipment required to analyze such very low-yield experiments is costly. The U.S. National Nuclear Security Administration (NNSA) is installing a $2 billion, 100-meter-long electron accelerator in a tunnel in its 300-meter-deep underground U1a subcritical testing facility in Nevada. The electrons will produce high-energy X-rays in a target outside the containment vessel to image the interior of the imploding plutonium mass. Neutrons will be injected to start the subcritical chain reaction, and gamma rays from the fissions will be measured to determine the rate at which the chain reaction dies away and thereby the degree of criticality that has been achieved.14

In 2019, the director of the U.S. Defense Intelligence Agency publicly accused Russia of “probably not adhering to the nuclear testing moratorium in a manner consistent with the zero-yield standard.”15 In 2020 the U.S. State Department indicated in its annual report, Adherence to and Compliance with Arms Control, Nonproliferation, and Disarmament Agreements and Commitments, that this conclusion had interagency support: “Despite Russia renewing its nuclear testing moratorium in 1996, some of its activities since 1996 have demonstrated a failure to adhere to the U.S. zero-yield standard, which would prohibit supercritical tests.”16 The report stated that the evidence was classified. It also expressed concern that “lack of transparency” at China’s Lop Nur test site “raise[s] concerns regarding China’s adherence to its test moratorium, which China declared in 1996, judged against the U.S. [subcritical] ‘zero-yield’ standard.”

As noted above, a 2012 review by the U.S. National Academy of Sciences could not “identify any significant advantage that could accrue to a state testing at…very low levels(<1 ton [TNT equivalent]).” A possible motive for Russia and China to carry out very low-yield supercritical or hydronuclear experiments could be because the degree of criticality of imploded plutonium pits is much easier to measure in a supercritical test, which produces many more fissions than a subcritical experiment and therefore many more diagnostic gamma rays. If Russia and China are conducting supercritical tests, perhaps it is because they do not want to match the more than $2 billion the United States is spending on its underground electron accelerator and other diagnostic equipment required for subcritical tests.

One can only speculate how the U.S. intelligence community concluded that Russia has conducted more than one supercritical experiment since 1996. One possibility could be that satellite images of Russia’s Novaya Zemlya test site have revealed large containment vessels such as a Kolba vessel being taken into the testing tunnels.

Jill Hruby, administrator of the U.S. National Nuclear Security Administration, speaking at a recent Comprehensive Test Ban Treaty (CTBT) conference, says the United States has “no plans” to resume the nuclear testing it halted in 1992 but will conduct “subcritical experiments.” (Photo courtesy of NNSA)Once the CTBT comes into force, any state-party may request a short-notice, on-site inspection of an area where it believes that a nuclear explosion or even a supercritical test may have taken place. Given that none of the remaining states that must sign and/or ratify the treaty have done so in recent years, however, the CTBT entry into force is years away. In the meantime, it would be advantageous to develop and demonstrate technical confidence-building measures through new methods and protocols that could determine whether contained experiments involving fissile material are subcritical.

At the 2023 CTBTO Science and Technology Conference in Vienna, U.S. NNSA Administrator Jill Hruby, whose organization maintains U.S. nuclear warheads, offered voluntary U.S. transparency, thus creating the possibility for international cooperation.

We are open to hosting international observers for monitoring and verification research and development on our subcritical experiments…. We are also open to working with others to develop a regime that would allow reciprocal observation with radiation detection equipment at each other’s subcritical experiments to allow confirmation that the experiment was consistent with the CTBT. We have several well-considered technical ideas on how this could be effective…. I sincerely look forward to future engagement with Russia and China on participation in bi- or tri-lateral verification confidence-building measures and other technological interactions to support future arms control and nonproliferation agreements.17

To date, these transparency proposals do not appear to have been detailed publicly or transmitted in a written form, and the Russian and Chinese governments have not accepted or rejected the offer.

Yet, there is a technical method to determine the amount of fission energy released by a contained, very low-yield test months or years later, by measuring the gamma rays from the radioactive decay of fission products and from transmutation products produced in the steel containment vessel as a result of irradiation by fission neutrons (fig. 1).18 Because the yields of supercritical experiments are typically orders of magnitude larger than those of subcritical experiments, such measurements would provide relevant evidence of a breach of the U.S. interpretation of zero yield.

Note: The gamma rays are from the radioactive decays of plutonium, fission products produced by chain reactions in the plutonium, and radioactive isotopes produced in the steel alloy of the containment vessel (CV) by irradiation from neutrons emitted by the chain reactions. The lines are labeled by the energy of the gamma ray in thousands of electron volts, the designation of the decaying radioisotope and the half-life of that isotope (or the of its parent isotope when the emitting isotope is the decay product of a longer-lived radioisotope).These verification methods would not be much help if a country does not announce all contained underground experiments or if it simply buries its containment vessels, as is the current custom, making them unavailable for inspection. To enable the implementation of verification after the test, a host country would have to agree not to bury or entomb a containment vessel before it is subjected to international inspection.

Continuity of knowledge for each containment vessel could be ensured by monitoring the tunnels or shafts through which containment vessels and plutonium could be introduced into the underground experimental complex. Each containment vessel could be tagged19 or “fingerprinted”20 for later identification. It is possible that this process could be managed remotely for the most part by CTBTO inspectors. Such an arrangement might be supplemented by remotely monitored on-site seismic stations to detect and localize contained underground explosions. The United States already has demonstrated such capabilities at its test site.21

As of mid-October, neither China nor Russia had responded to the U.S. proposal for reciprocal transparency at the three countries’ test sites.22 Given the high level of tensions between Russia and the United States over the war in Ukraine and between China and the United States, and the fact that the United States has not yet transmitted a formal written proposal, that is not surprising. Hopefully, in the longer term, the U.S. offer will open a path out of the destructive debate over possible but inconsequential Russian and Chinese violations of the U.S. interpretation of the CTBT.



1. Guy Faulconbridge and Filipp Lebedev, “Russian Duma Takes First Step to Revoke Ratification of Nuclear Test Ban Treaty,” Reuters, October 17, 2023.

2. In 1999, all but two Republican senators voted against ratification of the Comprehensive Test Ban Treaty (CTBT), and all but one Democratic senator voted in favor. Craig Cerniello, “Senate Rejects Comprehensive Test Ban Treaty; Clinton Vows to Continue Moratorium,” Arms Control Today, September/October 1999, https://www.armscontrol.org/act/1999-09/press-releases/senate-rejects-comprehensive-test-ban-treaty-clinton-vows-continue.

3. Egypt, Iran, and Israel have not ratified the CTBT. India, North Korea, and Pakistan have not signed the CTBT. Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), “Status of Signature and Ratification,” n.d., https://www.ctbto.org/our-mission/states-signatories (accessed October 21, 2023).

4. Vienna Convention on the Law of Treaties, May 23, 1969, 1155 U.N.T.S. 331, art. 18.

5. National Research Council, “The Comprehensive Nuclear Test Ban Treaty: Technical Issues for the United States,” 2012, fig. 2-8.

6. CTBTO, “Comprehensive Nuclear-Test-Ban Treaty (CTBT),” n.d., https://www.ctbto.org/sites/default

7. Office of the Spokesperson, U.S. Department of State, “Joint Statement on the Comprehensive Nuclear-Test-Ban Treaty by the Nuclear Nonproliferation Treaty Nuclear-Weapon States,” September 15, 2015, https://2009-2017.state.gov/r/pa/prs/ps/2016/09/261993.htm.

8. Bureau of Arms Control, Verification, and Compliance, U.S. Department of State, “Scope of the Comprehensive Nuclear Test-Ban Treaty,” n.d., https://2009-2017.state.gov/t/avc/rls/212166.htm (accessed October 21, 2023).

9. “Comprehensive Nuclear Test-Ban Treaty: Message From the President of the United States,” 105th Cong., 1st sess., Treaty Doc. 105-28, p. 4 (“Activities not affected by the treaty”).

10. Robert N. Thorn and Donald R. Westervelt, “Hydronuclear Experiments,” Los Alamos National Laboratory, LA-10902-MS, February 1987, https://www.osti.gov/servlets/purl/6646692.

11. National Nuclear Center of the Republic of Kazakhstan, “Nuclear Tests Consequences Elimination. ‘Kolba’ Containers Preservation,” May 9, 2022, https://www.nnc.kz/en/news/show/346.

12. “[O]ne benefit a State might gain from such very low yield tests would be to improve one-point safety. Such a step would not, standing alone, impair U.S. security.” National Research Council, “Comprehensive Nuclear Test Ban Treaty,” p. 104 fn.

13. David John Funk, “Enhanced Capabilities for Subcritical Experiments (ECSE): Portfolio Overview,” Los Alamos National Laboratory, LA-UR-18-28253, March 11, 2019, p. 46, https://permalink.lanl.gov/object/tr?what=info:lanl-repo/lareport/LA-UR-18-28253.

14. U.S. Government Accountability Office, “Program Management Improvements Would Benefit U.S. Efforts to Build New Experimental Capabilities,” GAO-23-105714, 2023, p. 7.

15. Hudson Institute, “The Arms Control Landscape ft. DIA Lt. Gen. Robert P. Ashley, Jr.,” May 29, 2019, https://www.hudson.org/national-security-defense/transcript-the-arms-control-landscape-ft-dia-lt-gen-robert-p-ashley-jr.

16. U.S. Department of State, “Adherence to and Compliance With Arms Control, Nonproliferation, and Disarmament Agreements and Commitments,” June 2020, p. 50, https://www.state.gov/wp-content/uploads/2020/06/2020-Adherence-to-and-Compliance-with-Arms-Control-Nonproliferation-and

17. Jill Hruby, Remarks at the CTBT Science and Technology Conference 2023, June 19, 2023, https://www.energy.gov/nnsa/articles/remarks-nnsa-administrator-jill-hruby-ctbt-science-and-technology-conference-2023.

18. Julien de Troullioud de Lanversin, Christopher Fichtlscherer, and Frank N. von Hippel, “Onsite Verification of the Comprehensive Nuclear Test Ban Treaty at Very Low Yields,” n.d., https://resources.inmm.org/sites/default/files/2021-09/a325.pdf.

19. Keith M. Tolk, “Reflective Particle Technology for Identification of Critical Components,” SAND-92-1676C, n.d., https://www.osti.gov/servlets/purl/7116334.

20. See Johannes Strömbom, “Natural Fingerprinting of Steel,” Luleå University of Technology, 2021, https://www.diva-portal.org/smash/get/diva2:1568687/FULLTEXT01.pdf.

21. National Research Council, “Comprehensive Nuclear Test Ban Treaty,” pp. 74-75.

22. Jonathan Tirone, “U.S. Offers Nuclear-Test Inspections to Ease Russia, China Tension,” Bloomberg, September 28, 2023.


Julien de Troullioud de Lanversin is an assistant professor in the Division of Public Policy at Hong Kong University of Science and Technology. Christopher Fichtlscherer is a doctoral graduate student at RWTH Aachen University. Frank N. von Hippel is professor of public and international affairs emeritus at Princeton University’s Program on Science and Global Security.

Given rising nuclear tensions involving China, Russia, and the United States, it is imperative that key states discuss a new transparency and verification regime for very low-yield nuclear tests.

Russia, the CTBT, and International Law

November 2023
By David A. Koplow

The recent decisions by the Russian Duma regarding the 1996 Comprehensive Test Ban Treaty (CTBT) have generated considerable legal and policy confusion. This analysis is an attempt to clarify the nature and consequences of those actions under international law.

Russia’s process is not an exercise of the “supreme national interests withdrawal clause,” which is contained in article IX of the CTBT and is common in other arms control agreements. That provision, like the rest of the treaty, is not operational until the treaty enters into force, which has not occurred. Article IX cannot be relied on by any state under the current circumstances and is not the basis for Russia’s recent actions.Instead, the next reference point is the 1969 Vienna Convention on the Law of Treaties, which sets forth the provisions regarding the conclusion, operation, and interpretation of international agreements. Article 18 of the convention establishes two circumstances under which a state is obligated to “refrain from acts which would defeat the object and purpose of a treaty” before the treaty enters into force.

The exact scope of the CTBT’s “object and purpose” is debatable. In 2016 the five nuclear-weapon states recognized under the nuclear Nonproliferation Treaty, which are also the permanent members of the UN Security Council (China, France, Russia, the United Kingdom, and the United States), issued a joint statement in which they authoritatively affirmed that a nuclear test would defeat the CTBT’s object and purpose. The entire Security Council subsequently endorsed that interpretation in Resolution 2310.

The first circumstance in which this obligation is operational is detailed in Vienna Convention article 18(a), which addresses the interval between a state signing and ratifying the treaty. That is the situation in which China, the United States, and a few others now stand regarding the CTBT. This obligation applies until the state “shall have made its intention clear not to become a party to the treaty.”

The mechanism for a state to specify its intention not to ratify a treaty, often incorrectly referenced as “unsigning” the treaty, is what the United States exercised regarding the 1998 Rome Statute establishing the International Criminal Court and the 2013 Arms Trade Treaty. In those cases, by expressing the intention not to ratify, the United States was released from the obligation to refrain from acts that would defeat the object and purpose of those treaties.

Russia has ratified the CTBT, so its recent actions are not governed by article 18(a). Instead, article 18(b) provides the same obligation to refrain from acts that would defeat the treaty’s object and purpose during the interval between ratification and the treaty’s entry into force “provided that such entry into force is not unduly delayed.”

In principle, a state perhaps could declare  that the CTBT’s entry into force has been “unduly delayed.” The treaty was opened for signature in 1996, but is unlikely to enter into force in the foreseeable future. Yet, Russia has not cited “undue delay.” Instead, it complained about the U.S. failure to ratify the CTBT and activities at the U.S. nuclear test site. Hence, the convention does not provide the mechanism for Russia to “unratify” the CTBT.

State practice regarding other treaties has rarely been tolerant of a withdrawal of a ratification prior to the treaty entering into force. The secretary-general of the United Nations, the usual depositary for multilateral treaties, occasionally has allowed a state to rescind a ratification without reference to or authorization by the convention. That presumably is what would happen here.

The final piece of the puzzle turns back to article 18(a) and raises the question of whether Russia’s withdrawal of its CTBT ratification also should be treated as an expression of an intention not to ratify the treaty again in the future. If so, the Duma’s action also could be interpreted as an “unsigning” of the CTBT, releasing Russia from the obligation to refrain from acts that would defeat the treaty’s object and purpose. More likely, the withdrawal of Russia’s ratification would not be interpreted as carrying that double effect, so Russia still would be regarded as a CTBT signatory obligated under article 18(a). That interpretation is reinforced by Putin’s comments about seeking “parity” with the United States regarding the CTBT; both states would now be obligated to refrain from acts that defeat the treaty’s object and purpose, including the obligation not to conduct nuclear tests.

In sum, Russia’s withdrawal of its CTBT ratification is not contemplated by the CTBT or the Vienna convention. Yet, it is an accepted, rare practice under international law. Russia thereby will achieve its objective of mirroring the United States regarding each country’s status under the treaty.

The withdrawal of ratification most likely has no practical legal effect. Russia, like the United States, would still be obligated as a signatory to refrain from acts that would defeat the treaty’s object and purpose, including nuclear testing. To date, Russia has not indicated any intention to violate its obligation under the convention by terminating its national moratorium.

David A. Koplow is the Scott K. Ginsberg Professor of Law at the Georgetown University Law Center.


Even after withdrawing its ratification of the Comprehensive Test Ban Treaty, Russia would still be obligated to refrain from nuclear testing.

Using Multilateralism to Fill the Space Policy Vacuum

November 2023
By Il-hoon Kim

The first series of meetings of the UN open-ended working group on reducing space threats through norms of responsible behaviors and actions came to a close on September 1 with two agreements: that there was no agreement and that a compromise is beyond the horizon.

Countries are increasingly dependent on a widening array of satellites in space. (Photo courtesy of Northrup Grumman)In fact, not even the title of a procedural report could be agreed. Arguably, this stems from a fundamental difference of philosophy on how space security should be governed internationally. Despite the overwhelming support for the report among states and civil society representatives in the working group, a handful of states abused the working group’s consensus rule and blocked the report. These states maintained a single-minded position that only legally binding instruments are meaningful. They refused to accept that the novel approach of cultivating a set of responsible behaviors to address the threats in, to, and from outer space enjoys wide backing from the international community, as evidenced by the fact that UN General Assembly Resolution 76/231, which established the working group, was adopted on a vote of 150-8.1

Four rounds of the working group were organized to implement the mandate of the UN resolution. It called for taking stock of the existing international legal and other normative frameworks concerning threats arising from state actions with respect to outer space and considering current and future threats by states to space systems and actions, activities, and omissions that could be considered irresponsible. In addition, the working group was charged with recommending to the General Assembly possible norms, rules, and principles of responsible behaviors relating to threats by states to space systems, including how such recommendations might contribute to the negotiation of legally binding instruments and prevent an arms race in outer space.

Except for a handful of states that opposed the working group from its inception, the majority of delegations involved in the deliberations over the last two years expressed support for this open, inclusive, and substantive platform and its mission to forge a consensus on concrete ways to enhance space security with the participation of all stakeholders.2 In a joint statement made at the closing session of the working group, 39 participating states reaffirmed that “political commitments on responsible behaviors can be developed in support of, and without prejudice to, the pursuit of legally binding measures and instruments in this area” and insisted that “these two approaches are not mutually exclusive.” They also appreciated the working group as “an excellent starting point that complements others’ efforts related to enhancing outer space security,” including the newly established group of governmental experts on the prevention of an arms race in outer space.

Notwithstanding, states that opposed the General Assembly resolution clearly showed that they would not allow consensus. Their key arguments against a behavior-based approach included that only a legally binding instrument can guarantee security in outer space; that the term “responsible behavior” is too subjective, vague, and unclear; and that capabilities, not behaviors, should be the basis of discussion. In short, these states asserted that the negotiation of the draft Treaty on the Prevention of the Placement of Weapons in Outer Space and of the Threat or Use of Force Against Outer Space Objects is the only viable way forward.

As plausible as they may sound, these arguments are faulty. First, the blind pursuit of legally binding instruments alone cannot ensure binding solutions. The war in Ukraine, intensified by Russia’s full-scale invasion in 2022, is a clear example. What good is a law that is not respected and that cannot be enforced effectively? The world need not be reminded that North Korea promised never to produce or acquire a nuclear weapon when it joined the nuclear Nonproliferation Treaty (NPT) in 1985 at the urging of the Soviet Union, which provided Pyongyang with nuclear research reactors. Nevertheless, North Korea developed its nuclear programs, announced its withdrawal from the NPT in 2003, has advanced its nuclear weapons program, and conducted six nuclear tests in the 21st century. There are countless examples of states violating their legal commitments.

The subjective nature of "responsible behaviors” also should not be a barrier to exploring proposals with which nations can agree. There is no disagreement that international law and norms should be based on objectivity. Yet, the international community also must not chase rainbows, believing that there is such a thing as an absolute good or objectivity in international affairs. Many if not most existing international laws and norms result from iterative processes. The act of war itself was not prohibited and was not even regarded as an irresponsible act before the difficult lessons learned through World War II were translated into the UN Charter. In other words, the working group and other consensus-seeking efforts provide valuable platforms by which to exchange views, shape converging ideas, and collectively confer objectivity on the norms that states can agree to follow. In addition, the objectivity of law, whether domestic or international, must undergo subjective perception and interpretation by those who implement and enforce it. Laws themselves are not static either.

One proposed set of tenets for responsible behaviors in space was put forward by U.S. Spacecom in March. (Graphic by U.S. Spacecom)Finally, the nature of space—the speed at which events occur and the dual-purpose characteristics of space systems—make capability-based prohibitions and their verification extremely difficult if not impossible at this stage of technological development. To date, weapons of mass destruction are the only type of weapons that are prohibited under existing international law (the 1967 Outer Space Treaty) from being stationed in orbit around the Earth or other celestial bodies.3 The sole purpose of the weapons of mass destruction is quite clear: to inflict mass destruction. There is no peaceful or commercial application, so it is easier to impose a legal ban. On the other hand, commercial or civilian satellites can be used beyond their original purpose, for example, as bullets that can apply kinetic force against other space systems. Robot arms on one satellite can be used to put other satellites off orbit or destroy them altogether. Governance of space security must take into consideration all of these critical and realistic characteristics as a legal ban could unduly restrict peaceful uses.

This is why the idea of norms, rules, and principles of responsible behaviors to address space threats was proposed to the international community by a number of states. Security threats involve action or inaction by a state that is deliberate, but the nature of space makes it impossible to verify that deliberateness or intent. As a result, many countries, including South Korea, have been ardent supporters of addressing space security threats through observable behaviors rather than prohibiting dual-use capabilities. Such prohibitions inevitably will have restrictive effects on the legitimate development and use of space. Banning robot arms, for instance, would mean that this capability cannot be used even for peaceful purposes, such as repairing satellites or rescuing satellites in distress.

This concern about deliberate threats also differentiates the space security norms now under discussion by the working group from the existing space safety governance mechanism led by UN Committee on Peaceful Uses of Outer Space. The UN committee was established by the General Assembly in 1959 to review international cooperation on the peaceful uses of outer space, study space-related activities that could be undertaken by the United Nations, encourage space research programs, and study legal problems arising from outer space exploration. Opponents of the behavior-based approach have been critical of the fact that safety issues must remain under the UN committee purview and that duplicity must be avoided. Risks or hazards, meaning consequences not caused by deliberate actions that potentially arise from peaceful space development activities, should continue to be regulated by existing international legal instruments, including the five outer space treaties and frameworks such as the UN committee.4 Issues pertaining strictly to space traffic management and other matters that are covered under guidelines adopted by the UN committee in June 2018 would fall under this category.5

Although duplication undoubtedly should be avoided as much as possible, the difference in the membership between the respective mechanisms and the importance of security issues must be given due consideration. For instance, only 102 states are members of the UN committee. Space security will have ramifications for the wider world, not just for space-faring nations, considering the growing global dependence on services provided by various space systems. For instance, a country could decide to destroy its own satellites, but the resultant debris likely will endanger the space systems of other states. The debris also could have a prohibitive effect on areas of space that otherwise could have been utilized for peaceful purposes if not now occupied by long-lived debris. Such problems caused by debris creation may fall under the purview of the UN committee, but the actions that caused the problem have a security origin and therefore cannot be addressed fully by confining the discussions to the handling of the aftermath of such events.

Closing the vacuum of norms is expected to bring realistic, tangible benefits to humanity as a whole. Among the benefits identified in the draft report of the chair of the working group are reducing threats to international peace and security related to activities in outer space, contributing to negotiations on a legally binding treaty or other instrument to prevent an arms race and war in outer space, and contributing to the long-term sustainability of outer space activities and the continuing and nondiscriminatory use and exploration of outer space.

In addition, the draft report cited the benefits of reducing the risk of misunderstandings, misperceptions, miscalculations, and unintended escalation and conflict; encouraging transparency and communication regarding space activities to avoid misinterpretation; and ensuring that private actors are accountable for their actions in outer space and fostering cooperation between states and private actors in the protection of space systems. Other benefits included encouraging the development and deployment of new technology consistent with international law.6

The rapid pace of technological advances and the advent of the new space era has made outer space increasingly congested, contested, and competitive. Many states and much of the world’s population are reliant on services provided by space systems. As a result, it would be detrimental and perilous to leave outer space void of any norms to govern the security dimensions. Threats emanate in all four vectors: earth to space, space to space, space to earth, and earth to earth. Threatening activities include launching space vehicles without coordinating beforehand with potentially affected countries; conducting rendezvous and proximity operations without prior notification, coordination, or consent; and testing or using destructive direct-ascent anti-missiles. Other potential threats include deliberately interfering with the command and control of space systems or impairing the ability of an operator to control a satellite and jamming or spoofing the signals of positioning, navigation, and timing satellites or interfering with such systems via cyberspace or other means.

A majority of UN member states aspire to create legally binding instruments to this end. Yet as reflected in the chair’s draft report, many working group participants “reaffirmed that possible solutions to outer space security can involve a combination of legally binding obligations and non-legally binding measures, and that work in both of these areas can be further pursued in a progressive, sustained and complementary manner, without undermining existing legal obligations”7 while recognizing that such nonbinding measures are not a substitute for legally binding arms control instruments.

The NG-11 Cygnus spacecraft, which is used to resupply the International Space Station and host payloads for experiments and technology demonstrations, is among the systems that could be at risk if UN efforts to reduce space threats are not successful. (Photo courtesy of NASA)Even so, a handful of states maintain the position that there can be no other way but the legally binding way. Such an all-or-nothing approach is unrealistic in light of today’s international security and diplomatic realities. What is more concerning is that the technologically less developed and resourceful countries likely will bear the brunt of the damage and disadvantage arising from the vacuum of norms, rules, and principles because they will not be in position to protect their rare assets in space by themselves. As such, the handful of resistant states is preventing the international community from collectively safeguarding the world by addressing and mitigating current and future space-related threats. A few states have abused the rule of consensus to effectively veto anything that deviates from their own legally-binding instruments, including the title of the working group itself. What states ought to be engaging in is multilateral consensus-driven negotiations to reach agreements on vital issues of common interest, thus guaranteeing the peace and predictable governance of outer space.

In light of the gravity and urgency of this issue, the open and inclusive platform provided by the working group must continue. Although the group of governmental experts8 will begin on November 20 in Geneva and provide another useful platform for discussing security in outer space, its closed setting, allowing only 25 national representatives as expert participants, cannot substitute for the working group in which all UN member-states and civil society can participate.

The next working group will need to pursue further in-depth discussions on concrete measures to reduce space threats in the form of voluntary yet politically binding pledges. Nevertheless, should the rule of consensus once again prove prohibitive to forging viable agreement on norms, rules, and principles of responsible behaviors governing space security, the international community should consider manifesting their shared interest in the form of a cooperative group in which states participate voluntarily. The benefits of this partnership would be shared mutually by the participating states but not extended to nonparticipants. If those countries willing to act responsibly can agree on concrete measures that allow such benefit sharing and if nonadmission proves disadvantageous to nonparticipants, such a cooperative has the potential to eventually incorporate large numbers of countries, ultimately leading to a viable, relevant, and sustainable set of international norm, rules, and principles.

The benefits of these responsible behaviors could include many elements in the chair’s draft report: notifying and consulting each other before space launches, conducting rendezvous and proximity operations, jamming or spoofing of signals, refraining from any acts that would impair the provision of critical space-based services to civilians, and sharing information on possible breaches of such actions by private sector actors. Another important outcome of such a cooperative could be the establishment of routine channels of communications to share information and to continue shaping the list of responsible behaviors. Sharing of real-time information on space situational awareness through a joint project or joint burden sharing could be another exclusive benefit that can be reaped by participants.

This type of cooperation would be possible because, unlike most traditional arms control arrangements, the novel approach taken by the working group is based on behaviors and not capabilities per se. If prohibitions or restrictions on development, acquisition, deployment, testing, or use of certain space and counterspace capabilities become the focus, it would be extremely difficult to establish such norms because there always would be the fear of cheating by nonparticipants or even participants due to the lack of a verification regime. This is another important contribution that the working group approach can make to the shared international efforts.

What is most important is to continue this important work. Disagreement over the working group title prevented the release of an official report, but it should not derail the international community from getting back to the right orbit.

Norms alone are not the silver bullet that will solve all problems, but they are undeniably an indispensable component of future space security governance. As UN Secretary-General António Guterres rightly pointed out at the UN Security Council meeting on April 24, states must recommit to make the prevention of conflict and crises a priority. Outer space is a critical realm that requires the revival of multilateralism before the damage becomes irreversible and out of control.



1. The eight members in opposition were China, Cuba, Iran, Nicaragua, North Korea, Russia, Syria, and Venezuela.

2. For instance, 32 international organizations, commercial actors, and civil society organizations attended the working group, along with an open invitation for all UN member states. See UN General Assembly, “List of Other International Organizations, Commercial Actors and Civil Society Organizations Attending the Open-Ended Working Group, in Accordance With Resolution 76/231,” A/AC.294/2023/INF.2, August 31, 2023.

3. See Treaty on Principles Governing the Activities of States in the Exploration and
Use of Outer Space, Including the Moon and Other Celestial Bodies, January 27, 1967, 610 U.N.T.S. 205.

4. For example, see UN Office for Outer Space Affairs, “Status of International Agreements Relating to Activities in Outer Space,” n.d., https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/status/index.html (accessed October 20, 2023).

5. Committee on the Peaceful Uses of Outer Space, “Guidelines for the Long-Term Sustainability of Outer Space Activities,” A/AC.105/2018/CRP.20, June 27, 2018.

6. UN General Assembly, “Draft Report of the Open-Ended Working Group on Reducing Space Threats Through Norms, Rules and Principles of Responsible Behaviours,” A/AC/294/2023/CRP.1/Rev.1, August 31, 2023.

7. Ibid., para. 7.

8. UN General Assembly, “Further Practical Measures for the Prevention of an Arms Race in Outer Space,” A/RES/74/34, December 18, 2019.

Il-hoon Kim, South Korea’s deputy permanent representative to the Conference on Disarmament in Geneva, is a former director of the Disarmament and Nonproliferation Division of the South Korean Ministry of Foreign Affairs. The author’s opinions are his own and may not reflect the position of the South Korean government.


Norms alone are not the silver bullet but they are an indispensable component of future space security governance.

A Not-So-Strategic Posture Commission

November 2023
By Adam Mount

For the first time since the collapse of the Soviet Union, U.S. nuclear strategy is at a crossroads.

The Congressional Commission on the Strategic Posture of the United States unveils its report on October 12 at the Institute for Defense Analyses in Washington. (Photo by Aliyah Averette of the Institute for Defense Analyses)The rapid expansion of China’s nuclear forces calls into question fundamental assumptions about how the United States can deter nuclear-armed adversaries. In this context, Congress appointed a bipartisan commission of 12 former government officials to assess the threat environment and make recommendations on the nation’s strategic posture. The final report of the Congressional Commission on the Strategic Posture of the United States, released in October, marks the start of an inchoate debate about how to respond to China’s buildup, the outcome of which will shape the U.S. nuclear arsenal for decades.

Although Biden administration officials clearly have articulated the challenge presented by China’s buildup, the 2022 Nuclear Posture Review presented a strategy to meet it.1 The commission’s report is the first attempt by an entity of the U.S. government to propose an answer to the problem of tripolar deterrence, defined by the former commander of U.S. Strategic Command as the need to deter “two nuclear-capable, strategic peer adversaries at the same time,”2 namely China and Russia. The Pentagon estimates that China’s deployed nuclear warheads have more than doubled since 2020, from 200 to 500, and projects them to more than double again by 2030.3 This increase, combined with expansions in Russian and North Korean nuclear forces, could double the number of nuclear weapons that U.S. forces are ordered to deter by 2035. The challenge is complicated by the need to deter what the commission calls “opportunistic or collaborative two-theater aggression.”

The problem of tripolar deterrence is far more complex than simple arithmetic. China’s buildup and the U.S. response pose significant risks to strategic stability, increasing the chance that adversaries could aggress against U.S. allies, that regional crises could advertently or inadvertently escalate to the nuclear level, and that limited nuclear use could expand into a strategic exchange. All other things being equal, a constant U.S. nuclear force cannot maintain the same strategy and hold twice the number of targets as it does now. Yet, U.S. strategy and other elements of the strategic posture do not need to be held constant. Developing a strategy to maintain strategic stability will require planners to assess a wide range of options, many of which present their own stability risks, fiscal or logistical challenges, or political problems when presented to U.S. allies and partners.

A Strategic Stability Strategy

One set of variables comprises nuclear posture: the numbers, types, positions, and alert status of U.S. nuclear forces. A strategy that depends solely on adjusting nuclear posture may ultimately succeed in holding the additional targets at risk, but may end up being unnecessarily slow or costly, may not help to deter other kinds of threats, or may inadvertently degrade strategic stability. A symmetrical response to China’s buildup is not necessarily the best response.

Many other variables could comprise critical parts of a strategy to maintain stability in the context of tripolar deterrence. For example, U.S. officials may consider how advanced conventional forces could help deter and respond to limited nuclear use in regional conflicts or affect a strategic exchange. Consistent with the Biden administration’s concept of “integrated deterrence,” officials may also seek to develop ways of imposing costs on an adversary by coordinating with allied nuclear or conventional forces or by using space, cyber-, economic, diplomatic, informational, or clandestine means to deny gains or impose costs.4 In many cases, non-nuclear options may be more flexible, credible, and less costly ways of producing the effects necessary to deter an attack.

In developing a strategy for tripolar deterrence, the U.S. president could also choose to adjust a range of parameters that structure nuclear planning, including the categories of assets that nuclear forces would target in specific contingencies, the quantity of damage required at different times after an enemy launches a strategic attack, the damage expectancy requirements attached to specific weapons systems against specific targets, or the level of risk they are willing to accept that a technological development could suddenly render a leg of the triad vulnerable. The president also may opt to issue updated guidance about how much risk he is willing to accept that an adversary could carry out a surprise disarming strategic attack or comes to doubt the credibility of available U.S. options for responding to limited nuclear use. Adjusting any of these parameters could change requirements for the number of U.S. weapons required to deter the growing arsenals of adversaries. Presidents customarily do not issue direct guidance on these kinds of specific parameters to affect nuclear planning, but they may have to do so if they intend to implement a deliberate strategy for tripolar deterrence.5

The first step toward a deliberate strategy of trilateral deterrence would be to reexamine, at a fundamental level, the purpose of U.S. nuclear weapons. The primary mission that determines the size and structure of U.S. strategic forces is to limit damage to the state and its allies should deterrence fail. A preemptive counterforce strategy, which depends on striking an adversary’s nuclear force before it is launched, is difficult to imagine for several reasons, not least of which is that, even in the best of circumstances, such a scenario would expose the U.S. homeland to several dozen nuclear attacks. A retaliatory counterforce strategy is equally problematic because, even in the best of circumstances, it would represent an attempt to limit damage after a catastrophic attack has already occurred. Any complete strategy for tripolar deterrence begins with answering these basic questions: Is damage limitation the primary mission of U.S. forces and, if so, how much damage and in what circumstances?

The Nimitz-class aircraft carrier USS Abraham Lincoln (CVN 72) and the Wasp-class Amphibious Assault Ship USS Kearsarge (LHD 3), showcasing an array of powerful U.S. military assets, sail during exercises in the Arabian Sea in 2019. A bipartisan congressional commission wants the United States to respond to two near-peer rivals, China and Russia, by building up more nuclear forces.  (Photo by Petty Officer 1st Class Brian Wilbur)Confronting these complex questions, the commission reached a simple answer: an across-the-board buildup of U.S. nuclear forces. Its report recommends pursuing increases in the size, diversity, and alert status of every nuclear system, including multiple warheads and road-mobile options for new intercontinental missiles, more cruise missiles, more bombers postured on continuous alert with more tankers to support them, more submarines, more capability to penetrate adversary air and missile defenses, and demanding requirements for new theater nuclear options to attempt to control escalations.

Despite evidence that development on homeland missile defense interceptors has stalled, the report recommends investing heavily in new programs and expanding their mission set beyond North Korea to include an ill-defined category of coercive attacks from Russia and China.6 Collectively, the proposals would reverse decades of initiatives from presidents of both parties to reduce reliance on nuclear weapons in favor of non-nuclear options that they considered more flexible. For the commission, tripolar deterrence is not a complex strategic problem but simply a deficit of nuclear weapons. Its answer to an arms race is an arms race.

The Commission’s Solution

The commission’s solution to the problem of tripolar deterrence is not a strategy. The report makes no attempt to specify the categories or numbers of targets that it believes must be held at risk and so does not provide estimates of how many additional systems to procure, when they will be required, or which to prioritize. The report rightly identifies a need to “deter or counter opportunistic or collaborative aggression” in multiple theaters, but it does not describe what this might look like or how it would affect U.S. plans and force requirements.7 Most importantly, the commission does not consider the significant risk that increases in U.S. nuclear forces could degrade crisis stability, thus increasing the risk of nuclear use. It is an arithmetic approach to the problem without the arithmetic.

Because it does not articulate its assumptions about what is required to deter U.S. adversaries, the report cannot explain why the commission believes current U.S. forces would be insufficient to inflict the required effects in relevant contingencies, the number of systems that would be required, or how a buildup in U.S. forces could meet their objectives given the likelihood that China and Russia would respond with further increases in their forces.8 The commission’s chapter on strategy states that “the basis for U.S. nuclear strategy is assured second strike,” but this standard cannot guide policy without an explanation of what they believe would constitute “unacceptable damage.”9 Adjustments to U.S. nuclear force structure could be part of a solution to the “two-peer problem,” but it is not a solution to suggest doubling the size of the U.S. arsenal without justifying the figure, as one commissioner did.10

The commission report also does not account for the major fiscal, logistical, and political constraints that would inhibit implementation of its recommendations. It acknowledges that its proposals “will drive extraordinary demands on the already-constrained” departments that manage the arsenal, but makes no attempt to offer recommendations that work within those constraints or realistic measures to loosen them.11 Instead, the report recommends a vast “overhaul and expansion of the capacity of the U.S. nuclear weapons defense industrial base” and the U.S. Department of Energy/National Nuclear Security Administration nuclear security enterprise and offers proposals that range from constructive to semantic to quixotic.12 Even if all of these specific steps were implemented, it is difficult to see how they add up to the enormous increase in capacity that would be required to enact the commission’s expanded force structure.

In practice, the commission’s answer to the two-peer problem will be far more influential on the gathering debate on the future of nuclear strategy than it is on actual U.S. policy. Because of the standing of the commission’s members and the political appeal of their findings, the commission’s answer likely will be accepted in many quarters as the default position. As the debate becomes detached from realistic options, it increases the risk that the United States never develops a coherent approach to the strategic challenge it faces.

The report should prompt a national debate on a strategy for tripolar deterrence. At present, no group has presented a viable alternative to a major expansion of the U.S. nuclear arsenal and its supporting infrastructure. In one recent article, three experts propose shifting away from targeting opposing warheads to targeting civilian infrastructure, which could be accomplished with relatively fewer warheads.13 This proposal is far out of step with the U.S. commitment to adhere to the law of armed conflict and so is unlikely to influence policy. By giving voice to the strawman constructed by advocates of a buildup, calls for countervalue targeting also does not help to promote a realistic debate on how to respond to the tripolar challenge.14 It may well be the case that an effective strategy for tripolar deterrence abandons any requirement for preemptive counterforce and accepts that assured second strike can be accomplished with a relatively smaller force, but the strategy must conform to the law of armed conflict to be implemented.

An effective strategy on tripolar deterrence will fall within the broad region between an infeasible buildup and an infeasible shift to civilian targeting. Developing that strategy will require reexamining some of the fundamental assumptions of U.S. nuclear strategy, including the value of damage limitation.

A constructive debate would consider not only the numbers and types of nuclear weapons in the U.S. arsenal, but it would explore how a broad set of variables can interact to enhance deterrence, ranging from the intricate parameters that guide nuclear planning to instruments in other domains of conflict.

Compelling recommendations will account for the significant and foreseeable constraints on U.S. options and the expected responses of adversaries. Most importantly, as the United States reevaluates its strategic deterrence posture, it should remember that its objective is to maintain strategy stability and reject policies that would degrade it.



1. Jake Sullivan, Remarks at the Arms Control Association Annual Forum, Washington, June 2, 2023, https://www.whitehouse.gov/briefing-room/speeches-remarks/2023/06/02/remarks-by-national-security-advisor-jake-sullivan-for-the-arms-control-association-aca-annual-forum/.

2. Aaron Mehta, “STRATCOM Chief Warns of Chinese ‘Strategic Breakout,’” Breaking Defense, August 12, 2021, https://breakingdefense.sites.breakingmedia.com/2021/08/stratcom-chief-warns-of-chinese-strategic-breakout/.

3. U.S. Department of Defense, “Military and Security Developments Involving the People’s Republic of China 2023: Annual Report to Congress,” October 19, 2023, https://media.defense.gov/2023/Oct/19/2003323409/-1/-1/1/2023-MILITARY-AND-SECURITY-DEVELOPMENTS-INVOLVING-THE-PEOPLES-REPUBLIC-OF-CHINA.PDF.

4. Stacie L. Pettyjohn and Becca Wasser, “No I in Team: Integrated Deterrence With Allies and Partners,” Center for a New American Security, December 2022, https://s3.us-east-1.amazonaws.com/files.cnas.org
; Adam Mount and Pranay Vaddi, “An Integrated Approach to Deterrence Posture,” Federation of American Scientists, n.d., https://fas.org/wp-content/uploads/2021/01/An-Integrated-Approach-to-Deterrence-Posture.pdf.

5. Sharon K. Weiner, “Resetting the Requirements for Nuclear Deterrence,” Arms Control Today, Vol. 52, No. 1 (2022): 12-16; Adam Mount, “The Biden Nuclear Posture Review: Obstacles to Reducing Reliance on Nuclear Weapons,” Arms Control Today, Vol. 52, No. 1 (2022): 6-11.

6. Congressional Commission on the Strategic Posture of the United States, “America’s Strategic Posture,” October 2023, p. 63, https://armedservices.house.gov/sites/republicans.armedservices.house.gov/files/Strategic-Posture-Committee-Report-Final.pdf.

7. Ibid., p. 31. See Keith B. Payne and David J. Trachtenberg, “Deterrence in the Emerging Threat Environment: What Is Different and Why It Matters,” Journal of Policy & Strategy, Vol. 2, No. 4 (2022): 3-51.

8. For a more modest, specific, and attainable response with a broadly similar approach to the commission, see Center for Global Security Research Study Group, “China’s Emergence as a Second Nuclear Peer: Implications for U.S. Nuclear Deterrence Strategy,” Lawrence Livermore National Laboratory, 2023.

9. Congressional Commission on the Strategic Posture of the United States, “America’s Strategic Posture,” p. 26.

10. “How Will America Deal With Three-Way Nuclear Deterrence?” The Economist, November 29, 2022.

11. Congressional Commission on the Strategic Posture of the United States, “America’s Strategic Posture,” p. 51.

12. Ibid., p. 60.

13. Charles L. Glaser, James M. Acton, and Steve Fetter, “The U.S. Nuclear Arsenal Can Deter Both China and Russia,” Foreign Affairs, October 5, 2023, https://www.foreignaffairs.com/united-states/us-nuclear-arsenal-can-deter-both-china-and-russia.

14. Keith B. Payne et al., “The Rejection of Intentional Population Targeting for ‘Tripolar’ Deterrence,” National Institute for Public Policy Information Series, No. 563 (September 26, 2023), https://nipp.org/wp-content/uploads/2023/09/IS-563.pdf.

Adam Mount is a nonresident senior fellow at the Federation of American Scientists.


For the bipartisan commission charged with recommending how the United States should deal simultaneously with two nuclear-capable adversaries, the “answer to an arms race is an arms race.”

Twenty-Five Years of Overt Nuclear India

October 2023
By Christopher Clary

What are the requirements of nuclear deterrence? How many nuclear weapons, and of what type, are needed to ensure national survival? These answers are not immediately apparent from careful deduction or induction. Different states have made different assessments, the same states have changed their assessments over time, and within states, there have often been harsh disagreements on the topic.

Indian soldiers in 1998 patrol shattered ground along the edge of the crater at the Pokhran Test Range where on May 11 and May 13 of that year the Indian government conducted five underground nuclear tests. (Photo by John MacDougall/AFP via Getty Images)When India opted to test nuclear weapons in 1998, the government offered what it argued would be a clear, definitive answer about what it sought to achieve with the tests: “credible minimum deterrence.” Nothing more was needed, but nothing less would do. Yet as such officials acknowledged even in the initial years, there was always a tension between the two adjectives that framed their nuclear thinking. That is, the need for credibility would inevitably pull up the requirements for deterrence beyond a minimum number of weapons. How much was the tricky part.

Now, 25 years later, Indian decision-makers have yet to conclude that they have met the requisite minimum needed for deterrence as they continue to pursue credibility. This pursuit has resulted in a slow but steady quantitative and qualitative modernization of the Indian arsenal. India pursues such steps even as Pakistan continues its own nuclear modernization and as China embarks on a nuclear expansion that is unparalleled in that nation’s nuclear history. Whether India’s deliberate pace is adequate to India’s credible but minimum deterrence needs will be a dominant question facing the country’s nuclear stewards in the coming decade.

Nuclear Tests and Afterward

In 1998, Indian Prime Minister Atal Bihari Vajpayee explained to U.S. President Bill Clinton that he had authorized new nuclear tests because he viewed a “deteriorating security environment” in the region. India faced an overt nuclear weapons state on its border, China, that had materially helped another neighbor, Pakistan, to become a covert nuclear state, he argued. Further, he explained, both countries had committed aggression against India in the past.1

India previously tested a nuclear explosive device in 1974, but framed that test publicly as a “peaceful nuclear explosion” rather than a weapons test. Although the peaceful appellation was not especially convincing to outsiders, the design of the device was not ruggedized or weaponized for delivery until renewed work on the project began in earnest in the late 1980s.2 Despite progress in secret, the semicovert nature of the program limited India in the steps it could take to deploy a ready arsenal. Some Indians thought it called into question the credibility of the deterrent, and others perceived an intolerable status deficit between India and other nuclear-armed states in the international system, a kind of “nuclear apartheid.”3

In these circumstances, India decided to conduct a brief series of nuclear explosive device tests on May 11 and 13, 1998. This overt testing triggered a short but intense round of nuclear weapons sanctions. Those sanctions proved transitory. By the end of the George W. Bush administration, Washington had shifted from treating India as a nonproliferation rogue to wooing India as a valuable strategic partner.

At the time of the 1998 tests, India’s ability to confront nuclear challenges from its regional foes was limited. New Delhi could deliver nuclear warheads only by aircraft or the short-range Prithvi-1 liquid-fueled missile, which had uncertain reliability even against many Pakistani targets and could reach only a small subset of Chinese population centers, notably not Beijing. Today, most nongovernmental analysts assess that India retains its aircraft-delivered weapons while adding four variants of the solid-fueled Agni missile family to the arsenal, with perhaps three more Agni variants in development. All of India’s land-based missiles are road or rail mobile. These aircraft-delivered and land-based elements are supplemented now by a seaborne leg with a few ship-based, short-range Dhanush ballistic missiles, which are of uncertain utility, and periodic operational deployments of a nuclear-powered submarine capable of carrying the short-range Kalam-15 (K-15) submarine-launched ballistic missile.

Today, India can target the entirety of Pakistan with a variety of nuclear-capable systems, while Indian coverage of the Chinese eastern seaboard remains limited. As India deploys newer variants of the Agni missile family and the longer-range Kalam-4 (K-4) and Kalam-5 (K-5) submarine-launched missiles, India’s ability to hold all of China at risk should be credible even to skeptical observers by the end of the decade. Although some sources refer to Indian cruise missiles, such as the BrahMos and Nirbhay, as nuclear capable, such sources are not authoritative. India may have sufficient fissile material for additional warheads, but most nongovernmental analysts assess that the government has deployed perhaps 160 warheads. Such a number, if correct, would place India at or near parity with Pakistan but substantially below estimates of the growing Chinese arsenal.4

Counterforce Temptations

In part out of sincere conviction and in part out of a desire to defuse international condemnation for its 1998 nuclear tests, India in subsequent years has promulgated a series of policy statements to showcase that its new nuclear deterrent would be at the minimum level possible while still appearing credible to India’s adversaries. New Delhi declared that it would adhere to a doctrine of no first use of nuclear weapons, thus underscoring its view that “the principal role of nuclear weapons is to deter their use by an adversary.” Indian officials “discarded” the possibility of nuclear war-fighting and promised that India would “not engage in any arms race.”5

Yet even as the government reiterated its commitment over the years to a no-first-use policy, a portion of India’s strategic community continued to question the wisdom of restraining India’s options during contingencies in which national survival would be on the line. By 2003, the Indian cabinet committee on security released a document on “operationalizing” the nuclear doctrine that made it clear India’s no-first-use commitment did not apply in the face of a major attack with chemical or biological weapons. Such a no-first-use commitment is arguably a mere caveat rather than a major doctrinal evolution, although the history of powers falsely or erroneously accusing one another of chemical or biological weapons use makes the caveat somewhat more worrisome.

Although his government promoted the doctrine of no-first-use of nuclear weapons, Indian Prime Minister Atal Bihari Vajpayee declared in 2000 that "If [Pakistanis] think we would wait for them to drop a bomb and face destruction, they are mistaken."  (Photo by Sondeep Shankar/Getty Images)Despite his government’s role in promulgating the no-first-use doctrine, Vajpayee himself was not always dogmatic in his public messaging on the issue. In 2000, in the face of what he viewed as unacceptable Pakistani nuclear threats, Vajpayee declared, “If [Pakistanis] think we would wait for them to drop a bomb and face destruction, they are mistaken.” Separately, multiple former Indian strategic force commanders have advocated for greater doctrinal ambiguity to permit rapid retaliatory or preemptive options in the event of likely adversary nuclear use. Some commanders even have argued that Indian leaders might have a moral obligation to consider preemptive counterforce nuclear strikes if they believed meaningful damage limitation was achievable.

At a minimum, there seemingly was widespread support within the military for the use of conventional weapons against nuclear or dual-use launch vehicles, and at least some civilians and military officers believed India should have the option to move beyond conventional counterforce to nuclear counterforce if need be. In 2016, India’s former defense minister stated that, “in a personal capacity,” he did not understand why India should “bind” itself publicly to a no-first-use commitment. That same year, a former Indian national security adviser wrote in his memoirs that a careful reading of Indian doctrine might permit the preemptive use of nuclear weapons as part of a broader argument that “India’s nuclear doctrine has far greater flexibility than it gets credit for.”6

When nongovernmental analysts began pointing out that such messages indicated that India might be shifting away from an ironclad no-first-use policy, such analyses did not prompt a full-throated refutation by Indian officials.7 Instead, Indian Defense Minister Rajnath Singh visited the Pokhran nuclear test site in August 2019, where he reiterated India’s prior commitment to a no-first-use doctrine but suggested that such a commitment might not be enduring. “India has strictly adhered to this doctrine. What happens in [the] future depends on the circumstances,” he said.8

Even with such developments as more advanced versions of the Agni nuclear ballistic missile, India seems far away from its deterrence goals, according to analyst Christopher Clary. (Photo by Sondeep Shankar/Getty Images)These ambiguities in signaling were accompanied by continued Indian capability developments that seemed at variance with the goal of a credible minimum deterrence. Although in the aftermath of the 1998 tests India initially had framed the doctrine almost exclusively in terms of the minimum requirements for credibility, the government subsequently articulated that its retaliatory strikes would be “massive and designed to inflict unacceptable damage.”

Massive retaliation is compatible with smaller arsenals, especially in contrast to flexible response or other nuclear war-fighting strategies, but India was silent on the sorts of targets that would face retaliatory strikes. Many informed observers argued that Indian doctrine was most consistent with a countervalue, city-targeting strategy. By refusing to retaliate until after India was attacked with nuclear weapons, government and military leaders would want to ensure that whatever force survived could still cause sufficient damage to deter even the most callous opponent. “With a no-first-use posture, if in the remote contingency that India is to respond to a nuclear attack, it would be most logical to use the weapons on cities instead of on purely military targets,” Indian analyst Manpreet Sethi assessed.9

Such a city-killing, massive retaliation strategy would reduce the technological burden faced by Indian scientists because an exquisite or large force was not required, merely a survivable one. This was consistent with prior Indian messaging that although the requirements of minimum credible deterrence were “dynamic,” they were not “open-ended.” As officials seemed to indicate in the initial years after the 1998 tests, India would have an arsenal to deter any plausible foe in the near future. This was not a never-ending journey but one with a reachable destination.

Twenty-five years later, New Delhi still seems far away from its deterrence goals. Some desired requirements seem imminently reasonable, such as the need to have at least a few dozen missiles capable of reaching targets as far as Beijing. Yet even today, most of the Indian nuclear arsenal is only able to reach western and central China. Other sought-after requirements are more debatable, such as the number of ballistic missile submarines India requires and whether submarine deterrence patrols need to be continuous or only occasional.

Still other decisions India has made seem incompatible with an arsenal designed for countervalue retaliatory attacks. Indian defense scientists have been eager to publicize that even their longer-range ballistic missiles have achieved a degree of accuracy that appears greater than necessary for countercity attacks. Their repeated announcements that tests across all missile types have achieved “pinpoint” accuracy with a “single-digit” and “close to zero” error rate suggests possible counterforce aspirations because such accuracy is not needed for the gruesome task of city killing. These advertised accuracy improvements have occurred alongside other changes in India’s posture, including apparent gains in the peacetime readiness of the arsenal. Such changes make it quicker and less detectable to prepare at least a subset of India’s nuclear weapons for use than it would have been in the early years of the program.

Taken together, these developments indicate that Indian officials are tempted by counterforce options, as demonstrated by their occasional but repeated public statements expressing skepticism about inalterable no-first-use commitments. As a consequence of this interest and as indicated by the capability developments, the Indian defense establishment has invested some energy and resources into making those options executable.

The pursuit of counterforce options might be incompatible with the spirit of the no-first-use doctrine, but it does not imply that India has or will soon change its declaratory doctrine. Such options might presage such a public change in policy, but Indian officials also might decide such mixed signals are useful, or in time they could reject counterforce options as infeasible. Hedging strategies are often difficult to distinguish from steadfast pursuit. This could be such a circumstance.

This interpretation of conscious bureaucratic intent is not the only conclusion that could be drawn from the available data. Other experts, such as former U.S. official Ashley Tellis, have argued that most Indian policymakers “are not well versed in the arcane terminology of nuclear deterrence theory” and thus any statements that are inconsistent with no-first-use adherence should be discarded. With regard to capabilities that are inconsistent with countervalue targeting, Tellis and others say that Indian scientists simply have exaggerated the capabilities that their systems have achieved and such claims should be discounted as promotional puffery and little more.10 Even if such braggart scientists view their primary audience as the Indian public, these recurrent capability claims reach external audiences as well. Because one primary goal of no-first-use doctrines is to reassure adversaries, public articulations of Indian doubts and caveats on the doctrine combined with these capability revelations serve at a minimum to undercut such reassurance.

Confronting a Chinese Sprint

In 2021 the United States charged that China was undertaking a significant, rapid expansion of its nuclear force. This intelligence assessment was buttressed by nongovernmental analysts with access to commercial satellite imagery who located sites in China that showed apparent large-scale construction of silos consistent with such an expansion. The U.S. Department of Defense projected that China “likely intends to have at least 1,000 warheads by 2030,” a substantial increase from prior assessments, which had placed the size of China’s nuclear warhead stockpile in the low 200s.11

As China accelerates and expands development of its nuclear arsenal, including with the DF-41 missile shown here in 2019, India is expected to increase its numbers of nuclear-capable systems. (Photo by Greg Baker/AFP via Getty Images)Since China acquired nuclear weapons in 1964, there has been a meaningful nuclear asymmetry between it and India. Prior to India’s 1974 nuclear explosive device test, that asymmetry was totally in China’s favor. After 1974, India was slow to weaponize its nuclear explosive design, and it struggled to produce a weapon that could strike major Chinese population centers. Even once Indian work on weaponization began in the late 1980s, Chinese targets could only be held at risk by Indian aircraft. Into the 1990s, when China had a remarkably limited ability to target the continental United States, India’s geographic proximity meant China had many delivery vehicles capable of reaching into India, including medium- and intermediate-range ballistic missiles and bomber aircraft. This asymmetry moderated a decade ago, when New Delhi finally deployed the Agni-2 and Agni-3 missiles. Only then did India have a credible means to reach many Chinese targets. It took several more years and the deployment of the Agni-4 missile for India to achieve the ability to credibly threaten major eastern coastal population centers in China, such as Beijing.

As India was securing a measure of nuclear parity, the new modernization effort by China has opened the prospect that China will sprint away from India quantitatively and perhaps qualitatively. Although Indian commentators have long maintained that New Delhi will not have to match Beijing’s expansion “warhead for warhead” or “system for system,” they have conceded, as one said, that “[o]bviously there is a need to adjust the numbers” of Indian weapons in the context of an accelerated Chinese buildup.12 The extent of the requisite numerical adjustment in Indian systems, however, has not been clarified.

One qualitative asymmetry that might exacerbate any growing numerical disparity is the perceived reliability and expected yield of India’s nuclear warheads. India’s 1998 tests were designed to test a weaponized fission design, but they also sought to validate a thermonuclear capability. There has been considerable controversy, including within the Indian nuclear scientific community, about whether that latter goal was achieved. Indeed, the widely perceived “under-performance” of the thermonuclear device in the 1998 tests calls into question whether India has a reliable boosted fission design, which in turn has implications for the probable yield of any weapons in India’s arsenal. India might have reliable warheads capable of small yields, similar to those achieved by the first-generation devices that destroyed Hiroshima and Nagasaki. It also might have unreliable warheads that are designed to achieve larger yields but in practice might fizzle.13

From the earliest days of the U.S. nuclear weapons program, there has been a debate about whether yields much larger than those associated with the first generation of fission weapons are truly necessary for deterrence. Many but by no means all Indian commentators have argued for the desirability of larger-yield devices, especially because only some remnants of India’s arsenal might survive an adversary’s first strike, thus making it necessary that the effects of only a handful of devices be sufficient to deter foes. In the words of one recent senior Indian military officer, “That our warheads have the capability of destroying cities in a single strike must be conveyed in the strongest terms.”14

This requirement seems unnecessary since even first-generation weapons can cause enormous, society-transforming destruction, especially given the population densities of modern Asia. A Nagasaki-equivalent device dropped on Chengdu in central China might not “destroy the city” in a literal sense, but it would destroy a meaningful portion of it and likely kill hundreds of thousands of people and injure hundreds of thousands more. Would a boosted fission device that killed more than a million people really change the calculus of any Chinese leader? Are there Chinese leaders who are willing to countenance 250,000 dead civilians per city but would draw the line at 1 million? There is no sure answer because leaders of other nuclear weapons states have often concluded differently, believing that bigger weapons and more potential dead would add meaningfully to the calculus of the living.

The stakes of such morbid calculations and associated debates are not merely abstract. The Russian war on Ukraine has caused renewed rumblings in Moscow that nuclear tests might be an advisable way to showcase the continued credibility of its deterrent. Such a development could trigger a cascade of tests by other states and cause India to reconsider whether another round of its own tests would be advisable.

An Arms Race in Southern Asia?

After India tested in 1998, officials were at pains to emphasize that they “refuse to participate in an arms race, including a nuclear arms race.” Yet such proclamations, previously quite common in the first decade-and-a-half of India’s overt nuclear age, appear to have disappeared since then from public speeches by Indian leaders.

China and India, of all the nuclear weapons states since 1945, have been the least concerned that relative nuclear inferiority might jeopardize nuclear deterrence. For China, the current nuclear modernization suggests that thinking is shifting. For India too, there have been signs that minimum credible deterrence might require larger, more capable arsenals than Indian leaders might have anticipated in the initial years after the 1998 tests. The future of stability in Asia and the health of the global arms control effort may depend on whether past relaxed views on deterrence were merely reflective of a transitory state of mind. If so and if Indian decision-makers come to believe that deterrence is more fragile than they initially assessed, then a new arms race in southern Asia seems virtually certain, although the pace and dangers of such a race may not be fully apparent for some years to come.



1. “Indian’s Letter to Clinton on the Nuclear Testing,” The New York Times, May 13, 1998,
p. A14.

2. See Vipin Narang, “Strategies of Proliferation: How States Pursue the Bomb,” International Security, Vol. 41, No. 3 (2017): 110-150; Gaurav Kampani, “New Delhi’s Long Nuclear Journey: How Secrecy and Institutional Roadblocks Delayed India’s Weaponization,” International Security, Vol. 38, No. 4 (Spring 2014): 79-114.

3. Jaswant Singh, “Against Nuclear Apartheid,” Foreign Affairs 77, no. 5 (September/October 1998): 41-52.

4. See Christopher Clary and Vipin Narang, “India’s Counterforce Temptations: Strategic Dilemmas, Doctrine, and Capabilities,” International Security, Vol. 43, No. 3 (Winter 2018-2019): 110-150; Ashley J. Tellis, “Striking Asymmetries: Nuclear Transitions in Southern Asia,” Carnegie Endowment for International Peace, 2022, https://carnegieendowment.org/files/202207-Tellis_Striking_Asymmetries-final.pdf; Hans M. Kristensen and Matt Korda, “Indian Nuclear Weapons, 2022,” Bulletin of the Atomic Scientists, Vol. 78, No. 4 (2022):
224-236; “World Nuclear Forces,” in SIPRI Yearbook 2023: Armaments, Disarmament and International Security (New York: Oxford University Press, 2023), pp. 294-299.

5. “Clarifying India’s Nascent Nuclear Doctrine: An Interview With Indian Foreign Minister Jaswant Singh,” Arms Control Today, December 1999, https://www.armscontrol.org/act/1999-12/featuresclarifying-indias-nascent

6. For a discussion of these and other quotes, see Clary and Narang, “India’s Counterforce Temptations.”

7. U.S. academic Vipin Narang first brought attention to several of these lines of evidence in early 2017. See Max Fisher, “India, Long at Odds With Pakistan, May Be Rethinking Nuclear First Strikes,” The New York Times, March 31, 2017.

8. Ministry of Defence, Government of India, “Raksha Mantri Shri Rajnath Singh Pays Homage to Former Prime Minister Atal Bihari Vajpayee in Pokhran on His First Death Anniversary,” August 16, 2019, https://pib.gov

9. Manpreet Sethi, “India’s Nuclear Doctrine: The Basis for Credible Deterrence,” Air Power Journal, Vol. 2, No. 2 (2007): 53.

10. Tellis, “Striking Asymmetries,” pp. 85, 117-118.

11. U.S. Office of the Secretary of Defense, “Military and Security Developments Involving the People’s Republic of China, 2021,” 2021, https://media.defense.gov/2021/Nov/03/2002885874/-1/-1/0/2021-CMPR-FINAL.PDF; U.S. Office of the Secretary of Defense, “Military and Security Developments Involving the People’s Republic of China,” 2020, https://media.defense.gov/2020/Sep/01/2002488689/-1/-1/1/2020-DOD-CHINA-MILITARY-POWER-REPORT-FINAL.PDF; Henrik Stålhane Hiim et al., “The Dynamics of an Entangled Security Dilemma: China’s Changing Nuclear Posture,” International Security, Vol. 47, No. 4 (2023): 147-187.

12. Air Marshal Rajesh Kumar, “Deterrence in Asymmetries,” Vivekananda International Foundation, September 12, 2022, https://www.vifindia.org/article/2022/september/12/deterrence-in-asymmetries.

13. Tellis, “Striking Asymmetries,” p. 106.

14. Kumar, “Deterrence in Asymmetries.”

Christopher Clary is an associate professor of political science at the University at Albany, State University of New York, and a nonresident fellow of the Stimson Center’s South Asia program.

Twenty-five years after their last nuclear weapons test, Indian decision-makers have yet to conclude that they have met the requisite minimum needed for deterrence.

Pakistan’s Evolving Nuclear Doctrine

October 2023
By Sitara Noor

In May, Pakistan commemorated the 25th anniversary of nuclear tests that were carried out in response to a series of nuclear blasts conducted by India a few weeks earlier.

The Nasr multi-tube ballistic missile is displayed during the Pakistan Day military parade in Islamabad in March 2015.  (Photo by Metin Aktas/Anadolu Agency/Getty Images)Islamabad’s decision to pursue a nuclear weapons program was largely shaped by its 1971 war with New Delhi, which led to the dismemberment of the country, and India’s first nuclear test, in May 1974. Faced with an escalating conventional imbalance vis-à-vis India, Pakistan saw nuclear deterrence as the primary means to establish strategic stability and dissuade India from engaging in a major future conflict. Since then, Pakistan has been trying to come up with solutions to what it deems destabilizing moves by India in the conventional and nuclear domains.

Although India publicly enunciated its nuclear doctrine in 2003, Pakistan, preferring ambiguity, did not make its doctrine public. Instead, it issued statements through various official channels from time to time to provide some insight into its nuclear policy. The deliberate ambiguity served Pakistan well and has allowed the country more flexibility to adjust its policy as India continued to evolve its conventional and nuclear posture.

The conception of Pakistan’s officially undeclared nuclear doctrine rests on formal statements from the civil and military leadership. This includes statements from the prime minister; press releases by the Inter Services Public Relations (ISPR), the media wing of the Pakistani military; and statements from other officials such as the foreign minister and Lt. Gen. Khalid Ahmed Kidwai, the founder and longtime director-general of the Strategic Plans Division.

Kidwai, in particular, regularly articulated policy positions in interviews and speeches in numerous national and international platforms while serving as the director-general of the Strategic Plans Division and, after retirement, as an adviser to the National Command Authority, the apex decision-making body that deals with all policy matters concerning nuclear weapons.

During a recent address at an event commemorating the nuclear test anniversary, Kidwai provided additional insights into Pakistani nuclear doctrine. Given his pivotal role in shaping this doctrine, his statements continue
to carry significant influence even in retirement and have ignited debate regarding potential shifts in the
country’s nuclear stance.

To understand the comments and their significance and potential impact on future policy, it is crucial to situate Kidwai’s speech within the broader context of Pakistani nuclear doctrine as it underwent various adaptations and alterations in response to changing regional dynamics and policies in India over the past two decades.

Enduring Features of the Doctrine

In contrast to India’s declared no-first-use nuclear policy, Pakistan decided not to endorse such a policy, thus leaving open the interpretation that Islamabad might use nuclear weapons first under certain circumstances. This has been a consistent, long-standing feature of the country’s nuclear posture. Given that the Pakistani nuclear arsenal serves as a deterrent against conventional aggression and nuclear threats from India, Islamabad deems it appropriate to maintain the first-use option. This is even more important for the country’s security because India’s no-first-use policy has been significantly diluted in recent years, as indicated by various official Indian statements.1

Unlike the Cold War practice, Pakistan views its nuclear weapons as an instrument of deterrence, and it is not seeking to obliterate the adversary in a splendid first strike or a bolt-from-the-blue-type attack. In that regard, Pakistan reportedly has kept its weapons in a de-mated form, meaning the warhead is separated from the delivery vehicle, with a strict centralized command-and-control system in place. Following the first successful flight test in 2011 of Nasr, also known as the Hatf-9, a solid-fueled tactical ballistic missile with a range of 60 kilometers, there were apprehensions regarding potential command-and-control challenges associated with its deployment. Nevertheless, Pakistan has maintained its position and reaffirmed assurances that it will continue to assert a centralized command and control over all missiles. This stance has remained consistent even after India’s advancements in the development of canisterized nuclear missiles.

Another enduring feature of Pakistani nuclear policy is a unilateral moratorium on nuclear testing underscored by Islamabad’s declaration that “it was not the first country to test and will not be the first to resume testing of nuclear weapons in South Asia.”2 Pakistan even offered to convert its unilateral moratorium into a bilateral commitment with India as a confidence-building measure. Nonetheless, India has not accepted this proposal, and there are signs that India may undertake another series of nuclear tests. Pakistan’s moratorium is subject to India’s decision in that regard. If India decides to resume nuclear testing at some stage, Pakistan is likely to follow suit.

Pakistan’s nuclear weapons and deterrence posture is defensive and India specific, unlike India, which has kept its policy more open-ended and avoided identifying specific potential adversaries in its doctrine. This foundational element of Pakistan’s nuclear posture has been highlighted officially since its nuclear tests in 1998. While speaking at the UN General Assembly in September of that year, just a few months after the nuclear tests, Pakistani Prime Minister Nawaz Sharif unequivocally stated that “Pakistan’s nuclear tests were conducted not to challenge the existing non-proliferation regime, nor to fulfill any great power ambition. They were designed to prevent the threat or use of force against Pakistan. Our tests in response to India thus served the cause of peace and stability in our region.”3

Following the 2011 U.S. military operation that killed al Qaeda leader Osama bin Laden in Pakistan, a discussion erupted over whether Pakistan might reevaluate its nuclear strategy to deter potential threats from its western border other than India. A similar argument has surfaced periodically suggesting Israel as a potential adversary for Pakistan. This argument gathered strength in view of the fact that Pakistan has no diplomatic relations with Israel and consistently takes a firm stance in support of the Palestinian cause against Israel in international forums. Likewise, the close defense ties between India and Israel, as well as Israel's alleged collaboration with India on potential air strikes against the nascent Pakistani nuclear program in the 1980s, contributed to this heightened sense of threat perception between the two countries.

This debate gained more traction with the testing in 2015 of Pakistan’s first intermediate-range ballistic missile, the two-stage, solid-fueled Shaheen III, having a range of 2,750 kilometers. Although Pakistan’s declared intent in developing the missile was to cover the entire Indian landmass including the Andaman and Nicobar Islands,4 there were concerns, particularly in the United States, about the Shaheen III potentially having the capacity to reach other targets, such as Israel. This debate resurfaces every now and then, but there has never been an official statement or any other indication of a shift to identify Israel as a potential target. On the contrary, Pakistan repeatedly has reiterated that its nuclear weapons program is only to deter threats from India. Likewise, the range of the Shaheen III was capped intentionally at 2,750 kilometers to allay any such concerns.

Evolving Trends

Pakistan started its nuclear program as a counter to India’s conventional superiority, particularly after losing its eastern territory in the 1971 war with India. Therefore, Pakistan’s nuclear policy has been inherently reactionary. As India’s nuclear and conventional posture changed over the years, so did Pakistan’s response, with some key inflection points being the 1998 nuclear tests and the development in the 1990s of a robust nuclear delivery infrastructure, including the Ghaznavi, Ghauri, and Shaheen missile systems, in response to India’s development of the Prithvi and Agni strategic missile series.

Pakistani army soldiers salute as they accompany a Shaheen III long-range ballistic missile during the Pakistan Day military parade in Islamabad in March 2016.  (Photo by Aamir Qureshi/AFP via Getty Images)Along the way, Pakistan has maintained a deliberate ambiguity about the size of its arsenal, its targeting options, and the thresholds for nuclear use. All these elements have evolved over the years in response to the evolving threat perception from India.

Credible minimum deterrence is another early tenet of Pakistan’s nuclear doctrine as laid out in various official statements. On May 20, 1999, a year after the nuclear tests, Sharif stated that, “in maintaining the nuclear deterrence, we remain acutely conscious of the risks and responsibilities arising from the possession of nuclear weapons.... Nuclear restraint, stabilization and minimum credible deterrence constitute the basic elements of Pakistan’s nuclear policy.”5 Further explaining the rationale and dynamism of this tenet, one Pakistani official maintained that “minimum cannot be quantified in static numbers. The Indian buildup will necessitate review and reassessment.”6

This inherent flexibility in Pakistan’s credible minimum deterrence posture has enabled the country to respond to shifts in India’s nuclear and conventional strategies. In light of India’s evolving Cold Start doctrine, which envisages a swift military action against Pakistan under the nuclear overhang, meaning trying to find an opportunity to attack Pakistan despite the threat of nuclear escalation, Islamabad transitioned toward what it called a “full spectrum deterrence” approach. Notably, Pakistan consistently has asserted its commitment to the fundamental principle of maintaining a credible minimum deterrence while resorting to full-spectrum deterrence. This shift toward full-spectrum deterrence was announced in 2011 in a press release after Pakistan’s first test of the Nasr tactical nuclear weapon.7 Expanding on this concept, Kidwai has asserted that, with a “full spectrum of nuclear weapons in all three categories—strategic, operational and tactical—[and] with full range coverage of the large Indian land mass and its outlying territories…[India would have] no place to hide.”8

More recently, Kidwai provided additional details on full-spectrum deterrence. Speaking at the Institute of Strategic Studies in Islamabad on May 24, he stated,

Pakistan’s full-spectrum deterrence capability, while remaining within the larger philosophy of credible minimum deterrence, comprises horizontally of a robust tri-services inventory of a variety of nuclear weapons…[that] is held on land with the Army Strategic Forces Command, the ASFC; at sea with the Naval Strategic Forces Command, the NSFC; and in the air with the Air Force Strategic Command, the AFSC. Vertically, the spectrum encapsulates adequate range coverage from zero meters to 2,750 kilometers, as well as nuclear weapons destructive yields at three tiers: strategic, operational, and tactical. India’s vast eastern and southern geographical dimensions are, therefore, entirely covered.… Pakistan possesses an entire range of weapons yield coverage in terms of kilotons…and the numbers strongly secured to deter the adversary’s declared policy of massive retaliation…. Pakistan retains the liberty of choosing from a full spectrum of targets in a target-rich India, notwithstanding the Indian indigenous ballistic missile defense capability or the Russian S-400, to include countervalue, counterforce, and battlefield targets.9

The statement offers insights into Pakistan’s evolving nuclear posture, highlighting recent developments, reiterating previously outlined features of the full-spectrum deterrence concept, and shedding light on potential future trends.

A bomb crater in a meadow in Balakot, a remote area of Pakistan, was left behind after an Indian fighter jet in 2019 attempted to strike a mountaintop building that New Delhi said was a militant training camp. (Photo by Pamela Constable/The Washington Post via Getty Images)Kidwai’s statement about “range coverage from zero meters to 2,750 kilometers” has piqued greater curiosity. Several national and international scholars have weighed in on the risks involved in adopting such a policy.10 Following the mounting debate over the logic of a range of zero meters, a clarification came in a tweet from a government-sponsored think tank. The tweet quoted Kidwai as saying that the reference to zero meters in his speech was just “metaphorical” and there was no change in the Pakistani missile ranges. The clarification indicates that toying with the idea of a range of zero, whether metaphorically or otherwise, may not directly reflect the official stance of the Strategic Plans Division or the National Command Authority. It implies, however, that such considerations may have existed to some degree in the periphery. Therefore, it is important to discuss the merits of any such policy that might have been under consideration at any level.

Kidwai’s clarification reiterates that there is no change in the range of nuclear missiles and the existing range of missiles from 60 kilometers to 2,750 kilometers shall remain sacrosanct for now. Nonetheless, it reinforces speculation that any potential change in the range, if at all, will amount to a change in the type of weapons system employed, for example, resorting to nuclear artillery or nuclear land mines.

Statements and a recent speech by Lt. Gen. Khalid Ahmed Kidwai, now retired, the founder and longtime director-general of Pakistan’s Strategic Plans Division, are being scrutinized for insight into Islamabad's nuclear policy. (Photo courtesy of Center for International Strategic Studies Sindh)Thoughts about resorting to lower-range weapons appears to be influenced by the growing belief in New Delhi that India’s 2019 airstrikes on Balakot, triggered by an alleged Pakistani-backed suicide attack on Indian forces in Pulwama, exposed a gap in Pakistan’s full-spectrum deterrence posture. With a lower range, Pakistan seems intent on plugging that perceived gap by lowering the nuclear threshold.

Regardless of the weapons system or range, any potential policy shift must weigh carefully the challenges and costs associated with it against the intended benefits. Especially in the nuclear policy domain, any shift should target specific strategic objectives rather than tactical advantages. Advocating a reduction in the nuclear threshold likely will lead to the latter, potentially overlooking the broader strategic costs associated with such a move.

A robust nuclear deterrence rests on the ability of the state to communicate the threat effectively while demonstrating the capability and resolve to carry out the threat. For deterrence to be effective, it is crucial for it to function within a specific operational range. If the nuclear threat surpasses a certain upper threshold, it could be perceived as implausible and consequently lose its effectiveness. Conversely, lowering the threshold too much carries the risk that the adversary might opt to absorb a low-yield attack and ultimately prevail on the political and diplomatic fronts. The essence of deterrence lies in the notion of inflicting unacceptable damage. If the threshold and yield are reduced to a point where the nuclear damage becomes tolerable or acceptable for the adversary, especially when weighed against potential nonkinetic political and diplomatic costs it may inflict on the adversary, the efficacy of deterrence could be compromised.

Notwithstanding the safety, security, and command-and-control challenges, the potential use of low-yield, shorter-range nuclear weapons with the aim to stop the Indians in their tracks may halt temporarily their advancement, but it is less likely to produce a major military advantage for Pakistan. On the contrary, it could be a diplomatic nightmare because it may open the floodgates of international condemnation for breaking the much-revered nuclear taboo.

Such a posture also goes against the primary concept of Pakistan’s nuclear deterrence, which views nuclear weapons as weapons of last resort that would inflict unacceptable damage on the enemy. The potential use of lower-yield nuclear weapons is neither the last resort nor potentially the cause of an infliction of unacceptable damage to the adversary, but as a first response, no matter how limited in yield, this approach would be enough to allow India to justify its massive retaliation response.

The potential change in the range also must be seen in the context of other elements of Kidwai’s speech. Another significant point was his reiteration of the importance of a full spectrum of targets, which include countervalue targets such as cities and civilian population centers and counterforce targets, including conventional and nuclear military targets, their associated infrastructure, and other logistics.

Pronouncements about a spectrum of targets and an emphasis on “countermassive retaliation” have been articulated in previous addresses,11 but their reiteration in conjunction with proposals to lower the nuclear threshold indicates a major shift from deterrence by punishment to deterrence by denial. This element has been duly noted by scholars who have highlighted that such an explanation of full-spectrum deterrence stands in sharp contradiction to the concept of credible minimum deterrence, which is a primary pillar of Pakistan’s declaratory nuclear policy.12 Likewise, there has to be convergence in the declaratory doctrine and its operationalization, otherwise deterrence could lose its credibility.13

Strengthening Deterrence

Since 2001-2002, India has worked simultaneously on two fronts. Diplomatically, it has pressured Pakistan with allegations about sponsoring terrorism in India and used this strategy as a pretext for avoiding bilateral talks to resolve issues with Pakistan. In contrast, Pakistan has struggled to garner international support on terrorism charges against India. Second, India is consistently advancing its conventional force posture with the aim of finding a way to attack Pakistan under the nuclear overhang. In addition to advancing its doctrine of limited conflict, India is transitioning gradually toward a nuclear war-fighting posture and contemplating preemptive counterforce first strikes against Pakistan.

Pakistan’s full-spectrum deterrence concept effectively has countered India’s plan to launch swift ingress into Pakistan under the Cold Start, or proactive, doctrine. Nevertheless, India’s purported surgical strikes in the wake of the Pulwama attack in February 2019 marked the first aerial skirmish between the two countries since their overt nuclearization. Following the Pulwama/Balakot crisis, in which Pakistan successfully responded to the Indian aerial aggression, both countries seem to have drawn contradictory lessons. From the Indian perspective, India has found a way to attack Pakistan under the nuclear overhang. Conversely, the Pakistanis believe their effective response has thwarted the perceived vulnerabilities that India sought to leverage.

The 2019 aerial exchange between the two nuclear-armed states underscored the importance of differentiating between theater-tactical-level deterrence and strategic deterrence. It also highlights the significance of conventional deterrence at the first rung of the escalation.14 Pakistan’s successful response in 2019 has proven that its conventional first response is effective, despite perceived weaknesses if it had to be employed in a long-drawn conventional war.

Therefore, in order to strengthen tactical-theater deterrence in an evolving strategic environment, Pakistan needs to further enhance its conventional strength. This will not only add strength to Pakistan’s nuclear deterrence posture, but would also be in line with Islamabad’s policy position of having “seamless integration between nuclear strategy and conventional military strategy” and using nuclear weapons as weapons of
last resort.15



1. Toby Dalton, “Much Ado About India’s No-First-Use Nuke Policy,” India Global Business, September 26, 2019, https://www.indiaglobalbusiness.com/igb-archive/much-ado-about-indias-no-first-use-nuke-policy.

2. Pakistani Ministry of Foreign Affairs, “Pakistan’s Policies on Arms Control, Non-Proliferation and Disarmament Issues,” n.d., https://mofa.gov.pk/acdis/ (accessed September 22, 2023).

3. “Text of Prime Minister Nawaz Sharif’s Speech at the UN: September 23, 1998,” Strategic Studies, Vol. 19/20 (1998).

4. “A Conversation With Gen. Khalid Kidwai,” Carnegie Endowment for International Peace, March 23, 2015, https://carnegieendowment.org/files/03-230315carnegieKIDWAI.pdf (transcript).

5. See Rodney W. Jones, “Minimum Nuclear Deterrence Postures in South Asia: An Overview,” U.S. Defense Threat Reduction Agency, October 1, 2001, n.39, https://www.globalsecurity.org/wmd/library/report/2001/south_asia.pdf.

6. Disarmament Diplomacy, No. 41 (November 1999) (quoting Pakistani Foreign Minister Abdus Sattar, November 25, 1999).

7. Inter-Service Public Relations, No. PR-94/2011-ISPR, April 19, 2011, https://www.ispr.gov.pk/press-release-detail.php?id=1721.

8. Khalid Kidwai, Address at “Defence, Deterrence and Stability in South Asia” workshop, Islamabad, December 13, 2016 (hereinafter 2016 Kidwai address).

9. Institute of Strategic Studies Islamabad, “Special Message by Lt. Gen. (Retd) Khalid Kidwai,” YouTube, May 25, 2023, https://www.youtube.com/watch?v=c3oOXOk3G1k.

10. For a detailed discussion on Pakistan’s evolving nuclear policy, see Ejaz Haider, “Nuclear Deterrence: Is the Last Resort the First Response?” The Friday Times, June 17, 2023; Adil Sultan, “The Next Decade of Nuclear Learning,” StrafAsia, May 28, 2023; Sitara Noor, “Did Pakistan Just Overhaul Its Nuclear Doctrine?” Foreign Policy, June 19, 2023, https://foreignpolicy.com/2023/06/19/pakistan-india-nuclear-weapons-zero-range-cold-start

11. 2016 Kidwai address.

12. Haider, “Nuclear Deterrence.”

13. Ali Ahmed, “Limiting a Subcontinental Nuclear War,” SP’s Land Forces, Vol. 11, No. 4 (August-September 2014), https://www.spslandforces.com/story/?id=317.

14. Syed Ali Zia Jaffery, “Enhancing Deterrence Stability on the Subcontinent: The Case for Conventional Deterrence,” Henry L. Stimson Center Visiting Fellow Policy Memo, April 8, 2020, https://www.stimson.org/2020/enhancing-deterrence-stability-on-the-subcontinent-the-case-for-conventional-deterrence/.

15. Khalid Kidwai, Keynote address and discussion session at “South Asian Strategic Stability: Deterrence, Nuclear Weapons and Arms Control” workshop, February 6, 2020, https://www.iiss.org/globalassets/media-library---content--migration/files/events/2020/transcript-of-lt-general-kidwais-keynote-address-as-delivered---iiss-ciss-workshop-6feb20.pdf.

Sitara Noor is a fellow in the Project on Managing the Atom at Harvard University’s Belfer Center for Science and International Affairs.

In order to strengthen tactical-theater deterrence in an evolving strategic environment, Pakistan needs to further enhance its conventional strength.

Behind the Scenes: How Not to Negotiate an Enhanced NPT Review Process

October 2023
By William C. Potter

When more than 100 delegations assembled in Vienna this summer for two sets of meetings to review the nuclear Nonproliferation Treaty (NPT), expectations among most diplomats were low.

Finnish diplomat Jarmo Viinanen chaired the first preparatory committee meeting for the 11th nuclear Nonproliferation Treaty Review Conference that was held July 31 to Aug. 11 in Vienna. (Photo by Dean Calma/IAEA)There was good reason for skepticism given the failure of the 10th NPT Review Conference in August 2022, the second consecutive conference that was unable to produce a consensus final document. More significantly, the international environment was even less welcoming than the previous year as Russia continued to wage its brutal war on Ukraine, Chinese-U.S. relations plummeted to their lowest level in decades, and prospects faded for resolving nuclear challenges in the Middle East and on the Korean peninsula.

It was a surprise, therefore, that the one-week meeting of the working group on further strengthening the NPT review process got off to a good start. Most delegates abandoned their standard practice of reciting highly scripted and predictable remarks in favor of more spontaneous, interactive deliberations. Delegates even appeared to listen to one another at the meeting, the first of its kind in the history of the NPT review process. Could it be that states were sufficiently frightened by a world in disarray that they had awakened from sleepwalking toward a nuclear catastrophe? Might they demonstrate the common sense and flexibility necessary to strengthen one of the few remaining international bulwarks against the spread of nuclear weapons? The short answer is no, but the manner in which negotiations collapsed at both events—the working group meeting and the first preparatory committee meeting for the 11th NPT Review Conference scheduled for 2026—is even more disturbing than their barren outcomes and bodes poorly for the future of multilateral nuclear diplomacy.

Searching for Solutions

The working group, which met July 24-28, was mandated by the 2022 review conference to “discuss and make recommendations to the preparatory committee on measures that would improve the effectiveness, efficiency, transparency, accountability, coordination, and continuity of the review process of the treaty.”1 The intent was not to renegotiate the 1995 decision to strengthen the review process, but to improve how the review process operated in order to make it more effective and efficient.2

Effectiveness and efficiency meant different things to different parties. Nevertheless, it quickly became apparent that although many states criticized the lengthy amount of time typically allocated to national statements at the opening of review process meetings and recognized the utility of appointing presiding officers earlier in the review cycle, their highest priority was enhancing accountability on the part of the nuclear-weapon states.

It was to be expected that non-nuclear-weapon states would attach importance to the need for NPT members to implement all past commitments, especially those related to nuclear disarmament. What was less obvious prior to the working group meeting was that France, the United Kingdom, and the United States, which with China and Russia are the five NPT-designated nuclear-weapon states, also would be amenable to reserving time at future meetings to discuss reports by the nuclear-weapon states about their nuclear weapons capabilities and doctrines.

Many different formulations for reporting were broached, but the one that enjoyed the most support was captured in the second draft set of recommendations submitted on the penultimate day of the meeting by Jarmo Viinanen, the Finnish chair of the working group. It proposed that the nuclear-weapon states should use a standard reporting template that identifies the number, type, and status of nuclear warheads and their delivery systems, as well as measures that had been taken to reduce the salience of these weapons in nuclear doctrines and policies.3

Although most states were comfortable with proposals to enhance accountability through greater transparency and standardized national reporting, disagreements arose about the appropriate frequency and scope of formal reporting, the application of reporting to all or selected treaty parties, and the desirability of having outside experts, including from civil society, comment on national reports and the implementation of past commitments. Russia, for example, maintained that each nuclear-weapon state should have the right to set limits on transparency with respect to reporting and argued that reporting should apply to all states regardless of their nuclear weapons status. It also objected to the proposed use of expert panels or, for that matter, any engagement by civil society in what it characterized as a treaty review process reserved for NPT states-parties. Too much interactive dialogue, Russia asserted, could lead people to “get off topic.” Russia also proclaimed, to the bemusement of many delegates, that other states did not appreciate the substantial financial burden frequent national reporting would place on Moscow.

Several other states also expressed reservations related to enhanced transparency and inclusivity in the reporting process. China, for example, argued that a state did not achieve disarmament by means of reporting, prompting Egypt to respond that although that might be true, so is the fact that disarmament is dependent on reporting. That said, Egypt joined Russia in opposing the use of outside experts and expressed concern that the working group should not overshadow the preparatory committee. In addition, Iran objected to any reference to the issue of inclusivity, which it asserted was extraneous to the treaty.

By the last day of the working group meeting, on July 28, Viinanen had submitted two versions of draft recommendations to the preparatory committee.4 In addition, at the afternoon session, he submitted a paper titled “Draft Decisions.”5 Many countries took exception to the title because they were not prepared for the working group to make any decision and objected to the omission of anything on transparency and accountability. The general sentiment was that one of the preceding documents on draft recommendations better captured the range of opinions that had been expressed during the group’s deliberations.

Progress, Then Frustration

At this point, the generally positive atmosphere that had characterized the first four days of the working group meeting gave way to frustration and recrimination as many delegations realized that there was little time left to make substantive recommendations before the preparatory committee meeting began its work the following Monday.

In response to this stalemate, a savvy young diplomat from the Philippines offered a proposal to try to preserve the earlier momentum. It recommended that time be reserved in future review process meetings to consider national reports, in particular those of the nuclear-weapon states, and to engage in discussions on the basis of the proposals that had been raised in the working group.6

Delegates to the preparatory committee for the 11th nuclear Nonproliferation Treaty Review Conference, which eventually would fail to produce a consensus document, meet in Vienna on July 31. (Photo by Dean Calma/IAEA)A diverse group of states, including Austria, Egypt, Ireland, Malaysia, Mexico, the Netherlands, and the United States, supported the general approach articulated by the Philippines. China indicated support for a “simplified version” of the proposal, while not specifying exactly what would be acceptable. The Russian delegation, however, remained a key outlier, arguing that it could not endorse the proposal because it was too late to receive instructions from Moscow.

Regrettably, the full record of these exchanges and those made earlier during the meeting are incomplete and impossible to document because the working group conducted its business, including the debate over the need for enhanced transparency, in private.7 What can be reconstructed is that as delegates approached the anticipated conclusion of the working group meeting, there was hope that a near consensus might yet emerge based on the Philippines proposal, as modified by Brazil, Canada, and Ireland.

Following a lengthy suspension of the meeting during which the heads of many key delegations huddled in the back of the conference hall with others looking on, four states produced a joint recommendation that time be reserved in future review process meetings for the consideration of national reports, in particular those of the nuclear-weapon states regarding the implementation of their NPT disarmament commitments. Moreover, they proposed that subsequent preparatory committee meetings in the current review cycle should continue these discussions with the objective of agreeing on recommendations to improve “the effectiveness, efficiency, coordination, continuity, transparency and accountability of the review process.” This would be based on a balanced consideration of the proposals presented during the working group meeting, including those in Viinanen’s second draft set of recommendations.

When the meeting resumed, most states still in the room welcomed the joint proposal as a compromise that preserved a record of many proposals to strengthen the review process without endorsing any specific recommendations. Even Iran, which had raised numerous procedural objections throughout the meeting, appeared to sense the shifting mood and did not object to the joint proposal.

Late that evening, Viinanen asked if delegations could accept the text proposed by the four states. The attention of all delegates was focused on the head of the Chinese delegation, Li Song. With much suspense, he announced that he had received permission from Beijing to accept the joint statement if specific reference to the conference document was omitted. This formula, although less than ideal, appeared to have the support of all delegations except Russia, which insisted that it could only endorse the joint proposal if it were substantially revised. At that point, Viinanen, recognizing the late hour and the fact that the heads of many delegations had already left the room, concluded that it would be impractical to continue further negotiations. He announced that he would issue a working paper containing draft recommendations under his own authority, and without further objections, the draft procedural report of the working group was adopted.8

The 2023 NPT Preparatory Committee

If the one-week working group meeting combined elements of meaningful dialogue and obstructionist behavior, the two-week preparatory committee meeting that followed was an exercise in futility that weakened the review process. Indeed, had it preceded the working group meeting, it is conceivable that the nearly 100 often repetitive statements during the general debate might have spurred NPT states-parties to adopt at least a few specific recommendations to reduce the inefficient use of time during meetings.

Izumi Nakamitsu (C), UN under-secretary-general of disarmament affairs, addresses delegates and participants at the July 31 opening in Vienna of the first preparatory committee for the 11th nuclear Nonproliferation Treaty Review Conference. (Photo by Dean Calma/IAEA)Instead, for the first nine days, the captive audience had to endure stale arguments that would make ChatGPT sigh. Many heads of delegations were pleased to excuse themselves from the meeting and conduct business elsewhere, and the most stimulating discussions about pressing nuclear dangers and how to deal with them typically were found at side events organized by civil society. The surreal quality of the preparatory committee debate led one diplomatic newcomer to the review process to ask, “What is the purpose of this exercise?” It was not an easy question to answer.

Even under the best of circumstances, review process deliberations tend to be tedious and only loosely connected to the most pressing nuclear challenges. At times, outside observers might be excused if they were to infer from the intensity of the debate that the most significant issues at stake were the time slot reserved for the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, the amount of time set aside for interactions with civil society, and the degree to which the meeting chair was an instrument of a particular regional or political grouping.

The preparatory committee meeting in Vienna was no different in this regard. Thus, various delegations complained about the unraveling of arms control agreements, the need to preserve the New Strategic Arms Reduction Treaty, the dangers of nuclear sharing, and the risks posed by attacks on civilian nuclear facilities.9 Little new was said, however, regarding the urgency of nuclear risk reduction, the actions required to halt the erosion of norms against nuclear weapons use, and the possibility of narrowing the gulf that separates the majority of states that view their security as threatened by the existence of nuclear weapons and those nuclear-weapon states and their allies that regard nuclear deterrence as indispensable for the preservation of international peace and stability. If anything, these issues received less consideration in Vienna than they had at the ill-fated NPT review conference in 2022.

To some extent, the uninspired debate can be attributed to the shorter-than-usual time available for preparation by delegates due to the accelerated review process schedule, after the more than two-year delay in holding the last review conference. It also reflects disagreements among states as to the primary purpose of preparatory committee meetings and the degree to which the first two sessions of every review cycle should include substantive negotiations on specific recommendations.

The overall dysfunctional nature of the latest preparatory committee meeting also was a result of the inability to compartmentalize nonproliferation negotiations from the acute political polarization apparent in almost all international forums. It is striking, for example, how traditional nonproliferation cooperation between Washington and Moscow, including in the NPT review process, is now nonexistent. Although its demise preceded Russia’s full-scale invasion of Ukraine and was especially noticeable at the 2018 NPT preparatory committee meeting, there is no longer any pretense of convergent interests on the part of France, the UK, and the United States on one hand and Russia and China on the other hand.

Today, Moscow also appears to attach less importance to the NPT review process than in the past as indicated by the relatively low rank of Russian diplomats in attendance. The head of the delegation was an acting deputy department director, while the very experienced Russian NPT diplomat, who is Moscow’s permanent representative to international organizations in Vienna, chose to go on vacation during the preparatory committee meeting.10 Although the presence of senior diplomats by no means assures a successful outcome, their absence complicates the ability to negotiate timely compromises.

Even more important to a successful negotiation than the engagement of senior diplomats is the presence of diplomats with a deep knowledge of review process negotiating history. This institutional memory of what worked and what did not is largely absent today because very few delegations possess members who were present at the 2010 or 2015 NPT review conferences, much less earlier ones. As such, diplomats often appear to be repeating statements made by their predecessors without an understanding of the flexibility in positions that made possible past compromises on very difficult disarmament, nonproliferation, and regional security issues.11

Also absent today is the presence of cross-regional groupings able to broker compromise language acceptable to the major NPT stakeholders. The New Agenda Coalition, which effectively played this role at the 2000 NPT review conference, remains active, but it is no longer able to bridge increasingly wide divides between and within regional and political groupings on disarmament issues. The broker role was difficult enough when there were relatively well-defined groupings with identifiable interests, but it is nearly impossible in an environment in which the nuclear-weapon states are extremely fragmented, with a much more assertive China, and the Non-Aligned Movement has more members and observers armed with nuclear weapons than any other grouping.12

The Chair’s Prerogative, or Not

No preparatory committee meeting has blessed a chair’s factual summary since 2002, when the innovation was first introduced at the mandate of the 2000 NPT review conference. Instead, the standard practice when consensus is unattainable has been for chairs to issue a summary of the meeting as a working paper on their own authority rather than as conference papers. This approach is not confined to the NPT review process, and the issuance of recommendations in the form of personal working papers is widely regarded as the prerogative of any chair at multilateral negotiations.

This practice was challenged in Vienna by Iran, which accused Viinanen of displaying a Western bias and promoting a summary that was neither factual nor impartial. Russia also objected to what it saw as an imbalance in the summary and a failure to note how NATO states allegedly used the meeting to advance political goals unrelated to the review process. China aligned itself with these critics and questioned if the chair had the authority to make recommendations to the next preparatory committee, although it did not explicitly deny the chair’s prerogative. That action fell to Iran, which announced that it would block the listing of the chair’s factual summary in any fashion, personal working paper or otherwise.

In fact, states-parties could have called Iran’s bluff and forced a vote on the matter, which Iran certainly would have lost. Yet, that would have brought into question the circumstances under which the tradition of consensus decision-making should be abandoned, and Viinanen was not prepared to venture into that uncharted territory. Instead, he acquiesced to Iran’s demand and withdrew his proposal to issue a factual summary under his own authority.13

Viinanen sought to downplay the harmful effects of this action by arguing that just as he had the prerogative to issue a working paper, he also had the authority not to do so, but the damage had been done. The 2000 NPT review conference mandate for preparatory committees to produce factual summaries was ignored. This outcome set an extraordinarily dangerous precedent by which one defiant state could negate the will of the conference majority and erase the record of what had transpired.

It remains to be seen if Iran’s ability to disrupt this year’s meeting will empower other outlier states to hold future multilateral negotiations hostage. Alternatively, perhaps this experience will spur a more serious debate about the circumstances under which states should be prepared to vote at NPT meetings and the merits of adopting a more liberal interpretation of what constitutes consensus.

The latest setback also could have the positive effect of encouraging states at future meetings to seek agreement on a much smaller set of new measures that are responsive to the most severe contemporary nuclear threats instead of endlessly debating a lengthy catalogue of recommendations that differ only marginally from those of the past. Were that to occur and if states emulated the positive interactive debate that occurred during much of the working group session, perhaps the Vienna meetings ultimately will contribute to strengthening the review process.



1. 2020 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons, “Decision on the Next Review Cycle,” NPT/CONF.2020/DEC.2, August 26, 2022.

2. Thomas Markram and Gaukhar Mukhatzhanova, “Further Strengthening the NPT Review Process: Reflections and Recommendations,” Vienna Center for Disarmament and Non-Proliferation and James Martin Center for Nonproliferation Studies, May 2023, https://vcdnp.org/wp-content/uploads/2023/06/NPT-SRP-paper-full-with-covers.pdf.

3. More specifically, paragraph 18 of the draft specified that national reports should identify

plans related to the modernization of nuclear weapons, and related changes to their nuclear capabilities; the number, type (strategic or non-strategic) and status (deployed or non-deployed) of nuclear warheads; the number and type of delivery vehicles; the measures taken to reduce the role and significance of nuclear weapons in military and security concepts, doctrines and policies; the measures taken to reduce the risk of unintended, unauthorized or accidental use of nuclear weapons; the measures taken to de-alert or reduce the operational readiness of nuclear weapons systems; the number and type of weapons and delivery systems dismantled and reduced as part of nuclear disarmament efforts; the amount of fissile material for military purposes.

Working Group on Further Strengthening the Review Process of the Treaty on the Non-Proliferation of Nuclear Weapons, “Draft Recommendations to the Preparatory Committee That Would Improve the Effectiveness, Efficiency, Transparency, Accountability, Coordination and Continuity of the Review Process of the Treaty on the Non-Proliferation of Nuclear Weapons,” NPT/CONF.2026/WG.I/CRP.2/Rev.1, July 28, 2023, para. 18, copy on file with author.

4. The first draft was submitted on July 26. The second draft was provided to delegates on July 28.

5. Working Group on Further Strengthening the Review Process of the Treaty on the Non-Proliferation of Nuclear Weapons, “Draft Decisions,” NPT/CONF.2026/WG.I/DEC.1, July 28, 2023, copy on file with author. There is no official record of this document or the second “Draft Decisions” paper that proposed to continue discussions on strengthening the review process at the first session of the preparatory committee for the 11th NPT Review Conference in 2026. See Working Group on Further Strengthening the Review Process of the Treaty on the Non-Proliferation of Nuclear Weapons, “Draft Decisions,” NPT/CONF.2026/WG.I/July 28, 2023, copy on file with author.

6. The proposal put forward by the Philippines, which was displayed on a video screen at the review conference, stated that

[t]he working group recommends that, consistent with the decision to improve the effectiveness, efficiency, coordination, continuity, transparency and accountability, as well to dedicate time in the formal meetings of the review cycle and to consider national reports of States Parties in particular nuclear weapons states in a manner than enables questions to be raised and clarifications to be made on the content of national reports, the Preparatory Committee engage in outcome-oriented discussions on the basis of a balanced consideration of all the proposals presented in the working group, including on formats and modalities.

7. For a list of the working papers submitted to the working group, see Reaching Critical Will, “Working Group on Further Strengthening the Review Process of the Treaty,” n.d., https://reachingcriticalwill.org/disarmament-fora/npt/2023/working-group (accessed September 20, 2023).

8. The chair’s working paper contained 26 recommendations, many of which mirrored those contained in the earlier draft documents, as well as recommendations broached in the article by Markram and Mukhatzhanova (See endnote 2). As a chair’s working paper rather than a conference paper, it lacked the imprimatur of the working group. See Preparatory Committee for the 2026 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons, “Working Paper Submitted by the Chair of the Working Group on Further Strengthening the Review Process of the Treaty on the Non-Proliferation of Nuclear Weapons: Recommendations to the Preparatory Committee That Would Improve the Effectiveness, Efficiency, Transparency, Accountability, Coordination and Continuity of the Review Process of the Treaty,” NPT/CONF.2026/PC.1/WP.34, August 3, 2023.

9. For a useful summary of the debate on these issues, see Gabriela Iveliz Rosa Hernández, Jupiter Kaishu Huang, and Daryl Kimball, “NPT Meeting Underscores Chronic Divisions,” Arms Control Today, September 2023.

10. The United States, by contrast, was represented at the meeting by three ambassadors.

11. In 2000, the New Agenda Coalition consisted of Brazil, Egypt, Ireland, Mexico, New Zealand, South Africa, and Sweden. Sweden subsequently withdrew from the coalition.

12. The composition of the Non-Aligned Movement always has been diverse, but never more so than with the recent addition of the Russian Federation as an observer.

13. Although Iran almost certainly would have lost a vote on the right of the preparatory committee chair to issue a working paper on his own authority, many states likely would have been reluctant to force a vote because they recognized that, in the future, they might be in the minority. Several key diplomats who were furious about Iran’s behavior nonetheless indicated privately that they were reluctant to call for a vote because of the precedent it would set.

William C. Potter is founding director of the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies at Monterey. He has participated as a delegate at every nuclear Nonproliferation Treaty review process meeting since 1995, including the two held in Vienna in July-August 2023.

The manner in which negotiations collapsed at two key nuclear Nonproliferation Treaty events bodes poorly for the future of multilateral nuclear diplomacy.

The Chemical Weapons Convention Is Stronger Than You Think

October 2023
By Stefano Costanzi 

On July 7, the United States announced that it had destroyed the last of its massive stockpile of chemical weapons.

The final munition in the U.S. chemical weapons stockpile, an M55 rocket containing GB nerve agent, was destroyed safely on July 7, 2023 at the Blue Grass Chemical Agent-Destruction Pilot Plant in Kentucky. It marked the total elimination of more than 30,000 tons of chemical agent in the original U.S. stockpile. (Photo by U.S. Army)Yet, the milestone extends far beyond this one country. It also marks the elimination of all of the world’s publicly declared chemical weapons. As reported by the Organisation for the Prohibition of Chemical Weapons (OPCW), which oversees implementation of the Chemical Weapons Convention (CWC), all 72,304 metric tons of declared chemical weapons stockpiles that CWC states-parties had accumulated before they ratified or acceded to the convention have now been destroyed.1

This remarkable achievement is testimony to the success of the CWC, an international treaty that imposes a complete ban on chemical weapons. Before the CWC entered into force in 1997, the main arms control treaty on chemical weapons was the 1925 Geneva Protocol, which banned the use of these weapons but not their development and stockpiling. Most countries interpreted the protocol as a “no first use” ban, meaning they could reserve the right to use chemical weapons in retaliation for a chemical weapons attack. As a result, chemical weapons were still produced and stockpiled. When the CWC took effect, things changed drastically because the treaty clearly mandated states-parties to declare and verifiably destroy their chemical weapons arsenals.

Even so, the chemical weapons threat has not been eradicated completely. A few countries did not sign the treaty, and some that did, such as Syria, appear to have retained undeclared stocks. This contributed to a tense atmosphere as states-parties held the fifth CWC review conference at The Hague in May.2 In addition to a troubled geopolitical situation, predominantly due to the war in Ukraine, states-parties have had to grapple with the fact that the treaty has been violated many times in recent years.3

In the Syrian civil war, chemical weapons were used more than 300 times between 2012 and 2019. Most of these attacks were attributed to the Syrian government and the rest to the Islamic State group. In February 2017, Kim Jong Nam, half-brother of North Korean leader Kim Jong Un, was assassinated in Malaysia with the nerve agent VX. In March 2018, Sergei Skripal, a former Russian intelligence officer, and his daughter, Yulia, were the targets of an assassination attempt in the United Kingdom. The attack was carried out using a nerve agent of the Novichok class, a group of highly toxic chemicals developed in the Soviet Union during the Cold War.4 Three months later, Dawn Sturgess, a woman who lived not far from the Skripals, died after serendipitously coming into contact with a discarded perfume bottle filled with the same Novichok agent, which had been found in a dumpster by her boyfriend. Following investigations, prosecutors from the British Counter Terrorism Division authorized charges against three members of the GRU, the Russian military intelligence service.5 In August 2020, Russian opposition leader Alexei Navalny was the target of another assassination attempt in Russia, with a different Novichok agent. Unsurprisingly, these incidents are regarded in strikingly different ways by different states, amid accusations, denials, and disinformation campaigns.

Despite the fact that the world is not yet completely free of chemical weapons and notwithstanding the tension that characterized the last review conference, the CWC undoubtedly is a very strong treaty that has significantly reduced the threat posed by this horrific category of weapons. Some work is still needed to keep the treaty and the organization that governs it current. This process risks being slowed down by the geopolitical situation, but a planning document produced by the OPCW Technical Secretariat indicates that constructive steps are being taken.6

A Strong Treaty

Fundamentally, the strength of the CWC as a robust disarmament and nonproliferation treaty rests on several pillars.7 Chemical weapons exploit the toxicity of chemicals to intentionally cause harm or death to humans or animals.8 The CWC is a comprehensive international treaty that poses a complete ban on chemical weapons, prohibiting not only the use of these weapons but also their development, acquisition, stockpiling, retention, and transfer. The CWC also prohibits military preparations to use chemical weapons, as well as the provision of assistance or encouragement to anyone to engage in activities prohibited by the convention.

One of the convention’s pillars is qualitative universality: the treaty is of unlimited duration and designed to be flexible enough to maintain its relevance in spite of changing circumstances. Above all, this is achieved through the so-called general purpose criterion under Article II, which establishes that any toxic chemical, unless intended for purposes not prohibited by the convention, is to be regarded as a chemical weapon. That means that the CWC prohibits all chemical weapons, present and future, including those that were unknown when the treaty was negotiated. Whenever a toxic chemical is developed into a chemical weapon, that weapon is automatically subject to the comprehensive ban posed by the treaty. In this sense, the CWC is similar to the Biological Weapons Convention (BWC), which poses an analogous comprehensive and general ban on biological weapons.

Henk Cor van der Kwast of The Netherlands (R), chairperson of the fifth Chemical Weapons Convention review conference, confers with Fernando Arias, director-general of the Organisation for the Prohibition of Chemical Weapons during the conference in May in The Hague. (Photo courtesy of OPCW)Another pillar is the convention’s quantitative universality: with 193 states-parties, the CWC enjoys near universal adherence. Israel has signed the convention, but has not ratified it. Egypt, North Korea, and South Sudan have not signed the treaty. According to the OPCW, “98 percent of the world’s population lives under the protection” of the CWC.9

The convention’s third pillar is its verification regime, which the BWC lacks. Chemical weapons destruction programs, as well as industrial activities, are subjected to a scrupulous process of declarations and verification.10 States-parties are required to submit annual declarations of yet-to-be destroyed stockpiles, production facilities, and activities that are not prohibited by the convention but involve chemicals that could pose a risk. Some of these declarations trigger on-site inspections by the OPCW Inspectorate. The verification regime is supported by three schedules of toxic chemicals and precursors for their synthesis that have been recognized as posing a chemical weapons threat.11

The Syrian Civil War

As paradoxical as it may seem, the Syrian civil war is perhaps the most evident example of the success of the CWC. The largest chemical weapons attack that occurred after the convention entered into force was in Ghouta on August 21, 2013. Surface-to-surface rockets hit this suburb of Damascus, releasing the deadly nerve agent sarin and causing the deaths of at least 1,200 people and perhaps more than 1,400, according to some sources. Many were civilians.12

Following these events, diplomatic initiatives led by Russia and the United States resulted in a framework for the destruction of Syria’s chemical weapons stockpiles. Syria then requested to accede to the CWC, and inspections of the Syrian declared stockpiles—more than 1,300 metric tons of chemical warfare agents and precursors—began in October 2013. Finally, through an international effort spearheaded by the United States, the destruction of declared Syrian chemical weapons stockpiles was completed in January 2016.13

This did not end the use of chemical weapons in the Syrian war. The Global Public Policy Institute, an independent think tank based in Berlin, counted a total of 349 confirmed chemical weapons incidents between 2012 and 2019, most of which occurred after Syria acceded to the CWC. According to the institute, almost all of these attacks are attributable to the Syrian government, while a handful is attributable to the Islamic State group.14 At first glance, this may seem like a treaty failure, but a closer look at the data reveals that the deaths caused by chemical weapons attacks decreased significantly after Syria joined the CWC.

A mother and father weep over the body of a child who was killed in a suspected chemical weapons attack on the Damascus suburb of Ghouta, Syria, on August 21, 2013. (Photo by NurPhoto/Corbis via Getty Images)According to the institute’s data, 1,444 people were killed in 38 chemical weapons attacks in Syria between December 2012 and October 2013, prior to the country’s CWC accession. The great majority of these deaths occurred in the 2013 Ghouta attack. Although many chemical attacks occurred after Syria became a CWC state-party, these attacks were significantly smaller in caliber, causing a total of 517 deaths in 311 attacks. This suggests that the OPCW-verified destruction of Syria’s declared chemical weapons arsenal had a profoundly positive impact on reducing the number of chemical weapons deaths.

Notably, the majority of the chemical weapons attacks after 2013 were perpetrated with chlorine, a toxic chemical that has vast legitimate applications, including for water sanitization. Its use as a weapon is indeed a flagrant violation of the CWC mandates, but due to chlorine’s legitimate uses, Syria was not restricted from accessing this material after joining the CWC. This explains its availability for use as a weapon throughout the war.

Nonetheless, unresolved and less than clear issues in Syria remain a cause of great concern. The OPCW has three active missions dedicated to investigating Syria’s compliance with the CWC: the Declaration and Assessment Team, which is working with the Syrian government to address issues that have been identified in the initial CWC declaration; the Fact Finding Mission, which is investigating alleged chemical weapons incidents in Syria and assessing whether they have actually occurred; and the Investigation and Identification Team (IIT), which is identifying the perpetrators of specific chemical weapons incidents in Syria.15

The IIT, which was established in 2018, has generated considerable controversy, with Syria and a minority of other states-parties, including Russia, claiming that its creation has overreached the OPCW mandate. In 2021, the CWC conference of states-parties suspended certain rights and privileges of Syria under the convention. These rights and privileges will be reinstated only after Syria satisfactorily complies with all measures requested by the conference. A minority of states-parties has asserted that Syria is in full compliance with the CWC mandates.

The Fifth Review Conference

The fifth CWC review conference, which took place May 15 to 19 in The Hague, provided an opportunity to highlight the successes of the convention in the last five years, and they were well summarized by the Canadian delegation’s statement.16 In addition to the fact that the destruction of the stockpile of chemical weapons under the CWC was about to be completed, these achievements include the construction of the OPCW Chemistry and Technology Center, a state-of-the-art facility that will help the OPCW keep up with chemistry developments and address emerging threats; the identification of perpetrators of several chemical weapons attacks; and the first amendment of the CWC schedules, or lists of treaty-regulated chemicals, since the convention’s entrance into force, with the addition of highly toxic Novichok and carbamate agents in 2019. In addition, in 2021 the conference of states-parties adopted a decision that clarifies that it is incompatible under the treaty to use aerosolized chemicals that act on the central nervous system, such as opioids, for law enforcement purposes.

Some of the more substantive issues raised at the review conference were covered by statements produced by representatives of nongovernmental organizations, academic institutions, think tanks, and advocacy groups.17 Importantly, the conference dedicated an entire hour to joint statements on topics coordinated by the CWC Coalition, an umbrella organization of civil society organizations.18 These issues included the need to maintain a world free of chemical weapons after completion of the destruction of the stockpiles declared by states-parties; strengthen the prohibition on the use of chemical weapons; prevent the acquisition of chemical weapons by nonstate actors, including terrorists and criminal organizations; promote full national implementation of the CWC mandates by all states-parties; and address problems caused by old chemical weapons that were discarded by dumping them at sea.

Reviewing the CWC Schedules

One of the joint statements coordinated by the CWC Coalition covered the need to realign the CWC schedules with the 21st century chemical weapons landscape.19 Under the treaty, any toxic chemical is considered a chemical weapon unless it is intended for a purpose that is not prohibited by the convention. Nevertheless, chemicals listed on the CWC schedules have a special status because they are subject unequivocally to declaration requirements and are the primary focus of OPCW inspectors and OPCW designated laboratories. The problem is that the CWC schedules, crafted when the convention was negotiated, are focused on toxic chemicals and precursors that had been relevant for 20th century chemical warfare. Although some chemicals were added to the schedules in 2019, action is needed to realign these lists with the current threat.

One problem area is the existence of chemical weapons agents and precursors for their synthesis that are currently unscheduled, including some Novichok agents and precursors for the synthesis of Novichoks and carbamates.20 Toxic chemicals that act on the central nervous system are another area of concern. Although many of these chemicals, such as opioids, are highly toxic, only a single central nervous system-acting chemical is currently listed on the CWC schedules: the hallucinogenic chemical BZ.

Biological toxins and bioregulators are also a concern.21 Biological toxins are toxic chemicals produced by living organisms, such as microorganisms, animals, or plants. Bioregulators are chemicals produced by the human body that have an effect on its functioning, for instance by affecting neurotransmission. Biological toxins are only minimally covered by the CWC schedules, while bioregulators are not covered at all.

UN arms experts arrive to inspect a site suspected of being hit by a deadly chemical weapons attack on August 28, 2013 in the Ghouta area near Damascus. (Photo by Mohamed Abdulla/AFP via Getty Images)The joint statement noted that the CWC schedules could be strengthened by improving the balance between the individual chemicals and families of chemicals that are listed, as well as revisiting the scope of some families of chemicals. Some entries in the CWC schedules identify families of related chemicals rather than individual chemicals. This approach contributes to the strength of the schedules, setting them apart from lists of chemicals exclusively based on the enumeration of individual chemicals. Listing families of related chemicals makes the CWC schedules more proactive and resilient to the passage of time, bringing under their coverage not only currently known chemicals but also related ones that could be developed in the future. The CWC schedules could be strengthened by replacing with families of chemicals some of the entries that currently identify single chemicals.22

At the same time, the CWC schedules could be streamlined by reducing the size of some of the listed families of chemicals that currently extend beyond chemicals that trigger chemical weapons concern. Such unnecessarily large families pose an avoidable burden on inspectors, laboratories that are tasked with conducting forensics analysis, export control officers, customs officials, and the chemical industry.

Circumscribing the scope of some families of chemicals is in line with a proposal presented by the U.S. delegation at a side event on the margins of the review conference. The proposal aims to streamline the verification regime for the largest family of chemicals in the CWC schedules. This would allow resources currently devoted to inspecting plants that work with chemicals that are recognized as not posing a threat to the mission of the CWC to be redirected toward more relevant issues. For example, resources spent to inspect textile industry plants that work with organophosphorus flame retardants that do not appear to have a role as precursors for the synthesis of nerve agents could be redirected to other, more pressing tasks.

Looking Ahead

As the review conference ended, there was no consensus on a final document to establish OPCW priorities for the next five years. Given the unstable geopolitical context, this was hardly a surprise. The fourth review conference, in 2018, also failed to reach consensus on a final document. The last review conference to produce a consensus document was the one held in 2013.23 All states-parties expressed regret at this year’s outcome. Russia blamed the stalemate on a lack of flexibility from some states-parties. The United States blamed states that still use chemical weapons.

Many participants, including the conference chair, Henk Cor van der Kwast of the Netherlands, attributed this outcome to the lack of time. Two weeks were allotted for previous review conferences, but only five days were given to this year’s meeting. Nevertheless, delegates praised the work Lauri Kuusing of Estonia, who chaired the working group responsible for preparing the conference, and José Antonio Zabalgoitia of Mexico, who chaired the committee of the whole, which provided the main forum for state-party efforts to reach consensus on a final document.

Although a final document proved elusive, it was clear from the closing statements of most national delegations that there was indeed consensus on most of the draft document. Despite the divergences, many states-parties expressed hope that the OPCW Executive Council and the conference of states-parties could follow up on issues on which there appears to be general agreement. They include strengthening the verification regime, which is fundamental to supporting chemical weapons disarmament and nonproliferation; increasing geographical representation within the OPCW; expanding the dialogue between states-parties and civil society; and expanding capacity building and international cooperation efforts.

It is encouraging that all these issues are addressed in the medium-term plan of the OPCW for the years 2024 to 2028 as prepared by the Technical Secretariat for the October 2023 meeting of the Executive Council. Even in the absence of a review conference consensus document, it is likely that the work that was done in preparation for the conference and during the conference itself can be leveraged and actualized by the states-parties during the next five years. The CWC mission has progressed significantly in the last five years, and that needs to continue.



1. Organisation for the Prohibition of Chemical Weapons (OPCW), “OPCW by the Numbers,” n.d., https://www.opcw.org/media-centre/opcw-numbers (accessed September 25, 2023).

2. OPCW, “RC-5: Fifth Review Conference,” n.d., https://www.opcw.org/calendar/rc (accessed September 25, 2023).

3. Rebecca Hersman and William Pittinos, “Restoring Restraint: Enforcing Accountability for Users of Chemical Weapons,” Center for Strategic and International Studies, 2018, https://www.csis.org/analysis/restoring-restraint; Stefano Costanzi and Gregory D. Koblentz, “Updating the CWC: How We Got Here and What Is Next,” Arms Control Today, April 2020; Stefano Costanzi and Gregory D. Koblentz, “Strengthening Controls on Novichoks: A Family-Based Approach to Covering A-Series Sgents and Precursors Under the Chemical-Weapons Nonproliferation Regime,” The Nonproliferation Review, Vol. 28, Nos. 1-3 (2021): 95-113.

4. Marcin Kloske and Zygfryd Witkiewicz, “Novichoks: The A-Group of Organophosphorus Chemical Warfare Agents,” Chemosphere, Vol. 221 (2019), pp. 672-682.

5. UK Counter Terrorism Policing, “Salisbury & Amesbury Investigation,” September 21, 2021, https://www.counterterrorism.police.uk/salisbury/.

6. OPCW Executive Council, “Note by the Technical Secretariat: Medium-Term Plan of the Organisation for the Prohibition of Chemical Weapons 2024-2028,” EC-104/S/1, C-28/S/1, August 14, 2023, https://www.opcw.org/sites/default/files/documents/2023/08/c28s01%20ec104s01%2B%28e%29_0.pdf.

7. Jean Pascal Zanders, “The Chemical Weapons Convention and Universality: A Question of Quality Over Quantity?” Disarmament Forum, Vol. 4 (December 2002), pp. 23-31.

8. Stefano Costanzi, “Chemical Warfare Agents,” Kirk-Othmer Encyclopedia of Chemical Technology, 2020, pp. 1-32.

9. OPCW, “Achieving Universality: Ensuring a Truly Global Treaty,” n.d., https://www.opcw.org/our-work/achieving-universality-convention (accessed September 25, 2023).

10. Ron G. Manley, “Verification Under the Chemical Weapons Convention: A Reflective Review,” Pure and Applied Chemistry, Vol. 74, No. 12 (2002): 2235-2240; OPCW, “Eliminating Chemical Weapons: Committed to Complete and Verifiable Destruction,” n.d., https://www.opcw.org/our-work/eliminating-chemical-weapons (accessed September 25, 2023).

11. Stefano Costanzi et al., “Lists of Chemical Warfare Agents and Precursors From International Nonproliferation Frameworks: Structural Annotation and Chemical Fingerprint Analysis,” Journal of Chemical Information and Modeling, Vol. 60, No. 10 (2020): 4804-4816.

12. Tobias Schneider and Theresa Lütkefend, “Nowhere to Hide: The Logic of Chemical Weapons Use in Syria,” Global Public Policy Institute (GPPI), February 2019, https://www.gppi.net/2019/02/17/the-logic-of-chemical-weapons-use-in-syria.

13. Organisation for the Prohibition of Chemical Weapons - UN Joint Mission, “Background,” n.d., https://opcw.unmissions.org/background (accessed September 25, 2023); Paul F. Walker, “Syrian Chemical Weapons Destruction: Taking Stock and Looking Ahead,” Arms Control Today, December 2014; Arms Control Association, “Timeline of Syrian Chemical Weapons Activity, 2012-2022,” February 2022, https://www.armscontrol.org/factsheets/Timeline-of-Syrian-Chemical-Weapons-Activity.

14. GPPI, “The Specter of Chemical Weapons Use in Syria,” n.d., https://chemicalweapons.gppi.net/ (accessed September 25, 2023).

15. OPCW, “Syria and the OPCW,” n.d., https://www.opcw.org/media-centre/featured-topics/opcw-and-syria (accessed September 25, 2023).

16. “Statement of Canada to the Fifth Review Conference of the Chemical Weapons Convention,” n.d., https://www.opcw.org/sites/default/files/documents/2023/05/Canada%20-%20CWC%20RC5%20National%20Statement.pdf.

17. For nongovernmental organization statements to the fifth Chemical Weapons Convention review conference, see OPCW, “Fifth Review Conference,” n.d., https://www.opcw.org/resources/documents/conference-states-parties/fifth-review-conference#NGO (accessed September 25, 2023).

18. CWC Coalition, “NGO Joint Statements,” n.d., https://www.cwccoalition.org/revcon5-ngo-statements/ (accessed September 25, 2023).

19. Stefano Costanzi, Michael Crowley, and Malcolm Dando, “NGO Joint Statement; The CWC Schedules: Addressing Scientific and Technological Advances in the Fourth Industrial Revolution,” n.d., https://www.opcw.org/sites/default/files/documents/2023/05/Joint%20NGO%20Statement%20-%20Statement%20on%20CWC%20Schedules%20.pdf.

20. Costanzi and Koblentz, “Strengthening Controls on Novichoks.”

21. Michael Crowley and Malcolm R. Dando, Toxin and Bioregulator Weapons: Preventing the Misuse of the Chemical and Life Sciences (Cham, Switzerland: Palgrave Macmillan, 2022).

22. Costanzi and Koblentz, “Strengthening Controls on Novichoks.”

23. OPCW, “Third Review Conference Concludes With Consensus Final Document and Political Declaration,” April 19, 2013, https://www.opcw.org/media-centre/news/2013/04/third-review-conference-concludes-consensus-final-document-and-political.

Stefano Costanzi, a professor of chemistry at American University, directs the university’s chemistry graduate programs and the Science and Policy Undergraduate Certificate.

Even though the world is not yet completely free of chemical weapons, the CWC has significantly reduced the threat.

The Delusions and Dangers of Missile Defense

By September 2023
By Jaganath Sankaran

The U.S. doctrine and posture on missile defense are in rapid flux.

The proliferation of advanced missile systems to regional actors has triggered an expansion of missile defense systems. Furthermore, as arms control agreements fade away and great-power competition reemerges, long-standing principles undergirding the link between homeland missile defense and strategic stability are being challenged. For instance, the House of Representatives draft of the 2024 National Defense Authorization Act (NDAA) has argued for amending U.S. doctrine to declare that homeland missile defense systems are now vital “to maintain a credible nuclear capability as the foundation of strategic deterrence.”1 Such a declaration would constitute a massive departure from the prevailing understanding of the role or, more accurately, the denial of a role for homeland missile defense in securing nuclear deterrence against near-peer adversaries.

China’s large arsenal of ballistic and cruise missiles, including this Dong Feng-26 (DF-26) intermediate-range ballistic missile, are among the threats driving the United States to invest increased spending on missile defense systems. (Photo by Xinhua/Cha Chunming via Getty Images)Historically, U.S. nuclear doctrine has insisted that homeland missile defense does not and cannot affect the strategic deterrent between major nuclear powers. For instance, the 2022 Missile Defense Review explicitly acknowledges that “the United States will continue to rely only on strategic deterrence” against Russia and China.2 Similar commitments have been consistently reiterated across administrations and by the U.S. Congress over several decades.

These doctrinal commitments are also enshrined in bilateral agreements, including the 2010 New Strategic Arms Reduction Treaty, which recognized the existence of an inverse interrelationship between strategic deterrence and homeland missile defense. That is to say, as an adversary state obtains more effective homeland defense, its ability to execute a disarming nuclear first strike increases. The treaty notes that
the “interrelationship will become more important as strategic nuclear arms are reduced.”3

The attempt to upend the doctrine is a hawkish stance and, in all likelihood, will fail. The Biden administration recognizes that such a move would portend significant adverse effects on strategic stability among the United States, Russia, and China. The administration has objected to the amendment to missile defense policy, noting in a Statement of Administration Policy that the proposed policy change will undermine strategic deterrence with Russia and China and overturn “two decades of well-established” policy on homeland missile defense.4 Despite the political desire to preserve the “well-established” policy, however, growing U.S. attempts to build a technologically advanced architecture of missile defense systems directly undermine strategic stability even if the intent is not to do so.

A Growing Threat

Various regional missile threats pose significant challenges for U.S. troops and allied states. A 2020 report by the National Air and Space Intelligence Center and the Defense Intelligence Ballistic Missile Analysis Committee declared that cruise and ballistic missiles would be used as “instruments of coercion” by adversaries seeking to end a crisis or a conflict with the United States or its allies on preferential terms.5

Three states—China, Iran, and North Korea—lie at the core of U.S. concern. Iran has the largest rocket, missile, and drone arsenal in the Middle East. A 2019 U.S. Defense Intelligence Agency report notes that Iran developed its arsenal to dissuade its regional adversaries and the United States.6 In June 2022, top military officials from Egypt, Israel, Jordan, Qatar, and Saudi Arabia secretly met U.S. military commanders to discuss ways to “coordinate against Iran’s growing missile” arsenal.7 North Korea has amassed a large arsenal of missiles targeting U.S. regional and allied targets throughout the Asia-Pacific region. These missiles could inflict significant destruction and death on South Koreans and deployed U.S. personnel. China possesses a large arsenal of ballistic and cruise missiles intended to generate “coercive political and military advantages in a regional crisis or conflict.”8 The bulk of China’s missile arsenal can reach regional airbases and port facilities that would be important in a regional military contingency involving the United States and its allies.

All these threats drive the impulse of U.S. policymakers to invest more in missile defense. The Biden administration has requested $29.8 billion for missile defense systems in the fiscal year 2024 budget, an increase of $5.1 billion from the previous year.9 The request includes $3.3 billion for the Ground-Based Midcourse Defense (GMD) homeland defense system, which is aimed at limited rogue threats such as North Korean intercontinental ballistic missiles (ICBMs). The other requests are directed at regional and theater missile defense, including $1.8 billion for the Aegis ballistic missile defense program, $574 million for the Terminal High Altitude Area Defense (THAAD) program, and $567 million for an integrated air and missile defense system in Guam.10

Yet, despite these investments, in reality the relative cost of defense is too high and favors the offense.11 It is much easier to innovate for the offense and defeat the defense with simpler tactics. The war in Yemen between the Houthi rebels and the Saudi Arabia-led coalition provides an illustration. The Saudis have relied on Patriot missile defense systems to defend against Houthi missiles. Each Patriot missile defense interceptor, however, costs approximately $1 million whereas the “flying lawn mowers” launched by the Houthis cost less than $10,000 each.12

Furthermore, the Houthis have found ingenious ways to defeat the Patriot systems by using drones to strike and damage the systems and then launching missiles before they could be fixed.13 A Saudi spokesperson has observed that “there is no country in the world being attacked with such amount of ballistic missiles.”14 The constant barrage of Houthi attacks has forced the Saudis to deplete their Patriot missile defense interceptor supply, requiring desperate efforts to replenish the inventory. Even for a wealthy state such as Saudi Arabia, missile defense systems offer short-term protection, not a long-term solution to missile strikes. Similarly, Russia’s never-ending use of missiles to bombard Ukraine demonstrates that missile defense can stall and weaken the thrust of the offense but cannot offer sustained protection.

The Perils of Unconstrained Missile Defense

The United States has spent more than $165 billion to experiment and produce the technological breakthroughs necessary to field an effective, limited homeland and regional missile defense system.15 Over the last two decades, the unconstrained experimentation has resulted in a globally distributed, technologically advanced architecture of missile defense interceptors, platforms, and sensors. Although these efforts have not shifted the advantage to the defense, they potentially can produce damaging consequences for strategic stability between major nuclear powers.

The Standard Missile-3 (SM-3) Block Interceptor, shown during a test over the Pacific Ocean in 2008, is among the systems being developed by the United States to defeat a threat from intercontinental ballistic missiles. (Photo by U.S. Navy via Getty Images)The architecture, in principle, portends the ability to realize a surprise breakthrough in strategic defensive capability against Russia and China. For instance, reacting to advances in North Korean ballistic missiles, the fiscal year 2018 NDAA mandated the U.S. Missile Defense Agency (MDA) to test the technological feasibility of the Standard Missile-3 (SM-3) Block IIA interceptor to defeat an ICBM threat.16 These interceptors initially were designed to defend against medium- and intermediate-range ballistic missiles. On November 16, 2020, the agency employed a ballistic missile defense-capable ship to launch an SM-3 IIA and intercept an ICBM-range missile.17 The use of these interceptors for homeland defense against North Korean ICBMs may now be de facto policy. In June 2021, Deputy Secretary of Defense Kathleen Hicks reportedly authorized the transfer of 11 SM-3 IIA interceptors from research to deployment after the successful flight test.18

The technological evolution in the performance of interceptors is further reinforced by a separate dedicated effort to advance the state-of-the-art sensor technologies supporting missile defense missions. The SPY-6(V)1 radar, performing a variety of missions including missile defense, originally had a programmatic requirement for a sensor to be 30 times more sensitive than the current SPY-1 radar deployed on ballistic missile defense-capable ships.19 Yet, the SPY-6(V)1 radar has turned out better than expected and is “nearly 100 times more sensitive” than the SPY-1 radar.20 Alternatively measured, the SPY-6(V)1 could track objects with similar signatures at approximately three times the range of SPY-1 radar. U.S. advances in missile defense radars have progressed alongside technological gains in space-based tracking and cueing.

Each of these technological capabilities, in its individual capacity, originated as a way to defend against regional threats, but the summation of these accumulated technological capabilities has a much larger strategic impact than their individual parts. A three-fold increase in the tracking range of the organic radar sensors of ballistic missile defense-capable ships armed with interceptors capable of homeland missile defense missions significantly expands the capabilities of these platforms. Additionally, the MDA has proposed a layered homeland defense architecture consisting of the GMD system augmented by underlayers of SM-3 IIA and THAAD interceptors.21

Such a layered homeland missile defense architecture may rapidly expand the number of interceptors and opportunities for interception from the tens to the hundreds. It could provide, in principle, a significant capability for strategic defense against Russian and Chinese missiles. A homeland defense shield buttressed by a shoot-look-shoot GMD system that can pursue two distinct intercept attempts, followed by the SM-3 Block IIA interceptors as an underlayer and THAAD interceptors for terminal defense, cannot reasonably be claimed to be limited.22 Such a multilayered missile defense architecture would be viewed as highly destabilizing and catalyze an arms race.

Rethinking Missile Defense

U.S. missile defense efforts have produced a worst-of-both-worlds situation. On the one hand, against increasingly sophisticated regional missile threats, the efforts to deploy a robust regional missile defense shield appear improbable. At the same time, the growing pace of North Korean capabilities and systemic U.S. technical failures raises severe doubts about the viability of the GMD homeland missile defense system.23 On the other hand, the accumulation of a range of technological capabilities to support the missile defense mission undermines strategic stability.

U.S. Secretary of Defense Robert McNamara, discussing U.S. fears of a Soviet technological breakthrough in missile defense systems in 1967, observed that it did not make “much difference what the evidence indicates…because I believe we must assume for planning” purposes that a system with the probable characteristic of a missile defense system can at some future point emerge as a capable defense.24 Throughout the 1960s, U.S. nuclear war planners espoused a greater-than-expected threat metric to offset any future Soviet technical breakthroughs in missile defense. Similarly, prudence requires Russian and Chinese analysts to assume any limited U.S. system is a stalking horse for a more substantial defense. If worst-case planning is the baseline to determine requirements for strategic deterrence, Russia and China could easily postulate imminent U.S. qualitative and quantitative breakthroughs.

A Russian Yars intercontinental ballistic missile launcher crosses Red Square during the Victory Day military parade in May 2022. (Photo by Alexander Nemenov/AFP via Getty Images)After the end of the Cold War, U.S. policymakers were willing to suspend the logic of strategic stability in the pursuit of missile defense. Yet, such a posture is no longer possible. The United States has declared the reemergence of great-power competition. The 2022 Nuclear Posture Review asserts the emergence of two major nuclear powers, Russia and China, as U.S. strategic competitors and potential adversaries. The review acknowledges “new stresses” on stability and deterrence.25 The pursuit of unconstrained missile defense systems is one of those stressors. U.S. efforts to maintain a viable homeland and regional missile defense have reached the point where the vector sum of the emerging capabilities of the various interceptors and sensors already surpass, in theory, the requirements of a highly capable homeland defense that could function against major nuclear powers.

A rethinking of the logic and purpose of the U.S. missile defense enterprise is urgently needed. First, the role of defensive and offensive forces against regional missile threats has to be reexamined in light of recent experiences, including the Russian war against Ukraine. Missile defense in a regional context may play niche roles, but it cannot be the essence of the U.S. deterrent and war-fighting strategy. Second, technology creep continues to erode the separation between regional and homeland systems. U.S. policymakers must institute clear limits to highlight the separation between these systems. Finally, policymakers also must explore arms control measures to constrain regional ballistic missile arsenals.

Although arms control diplomacy appears infeasible in the prevailing geopolitical environment, a treaty akin to the Intermediate-Range Nuclear Forces Treaty constraining ballistic missile proliferation and missile defense systems simultaneously would address the concerns of the United States, Russia, and China. Such arms control efforts may become viable in the future, and Washington must be prepared to seize any opening.


1. National Defense Authorization Act for Fiscal Year 2024, H.R. 2670, 118th Cong.
(2023) (House engrossed version), https://www.congress.gov/118/bills/hr2670/BILLS-118hr2670rh.pdf.

2. U.S. Department of Defense, “2022 Missile Defense Review,” October 27, 2022, p. 5, https://media.defense.gov/2022/Oct/27/2003103845/-1/-1/1/2022-NATIONAL-DEFENSE-STRATEGY-NPR-MDR.PDF#page=71.

3. Treaty Between the United States of America and the Russian Federation on Measures for the Further Reduction and Limitation of Strategic Offensive Arms, April 8, 2010, https://2009-2017.state.gov/documents/organization/140035.pdf.

4. U.S. Office of Management and Budget, “Statement of Administration Policy: H.R. 2670 - National Defense Authorization Act for Fiscal Year 2024,” July 10, 2023, p. 4, https://www.whitehouse.gov/wp-content/uploads/2023/07/H.R.-2670-NDAA.pdf.

5. National Air and Space Intelligence Center and Defense Intelligence Ballistic Missile Analysis Committee, “2020 Ballistic and Cruise Missile Threat,” July 2020, p. 4, https://media.defense.gov/2021/Jan/11/2002563190/-1/-1/1/2020%20BALLISTIC%20AND%20CRUISE%20MISSILE%20THREAT_FINAL_2OCT_REDUCEDFILE.PDF.

6. Defense Intelligence Agency, “Iran Military Power: Ensuring Regime Survival and Securing Regional Dominance,” 2019, p. 30, https://www.dia.mil/Portals/110/Images/News/Military_Powers_Publications/Iran_Military_Power_LR.pdf.

7. Michael R. Gordon and David S. Cloud, “U.S. Held Secret Meeting With Israeli, Arab Military Chiefs to Counter Iran Air Threat,” The Wall Street Journal, June 26, 2022.

8. Office of the U.S. Secretary of Defense, “2019 Missile Defense Review,” 2019, p. v, https://www.defense.gov/Portals/1/Interactive/2018/11-2019-Missile-Defense-Review/The%202019%20MDR_Executive%20Summary.pdf.

9. Office of the Under Secretary of Defense, Comptroller/Chief Financial Officer, “United States Department of Defense Fiscal Year 2024 Budget Request,” March 2023, p. 7, https://comptroller.defense.gov/Portals/45/Documents/defbudget/FY2024/FY2024_Budget_Request.pdf. For a comparison to the previous fiscal year, see Center for Arms Control and Non-Proliferation, “Fiscal Year 2024 Defense Budget Request Briefing Book,” April 4, 2023, https://armscontrolcenter.org/fiscal-year-2024-defense-budget-request-briefing-book/.

10. Center for Arms Control and Non-Proliferation, “Fiscal Year 2024 Defense Budget Request Briefing Book.” See also Office of the Under Secretary of Defense, Comptroller/Chief Financial Officer, “United States Department of Defense Fiscal Year 2024 Budget Request, https://comptroller.defense.gov/Portals/45/Documents/defbudget/FY2024/FY2024_Budget_Request.pdf.

11. Jaganath Sankaran, “Missile Wars in the Asia Pacific: The Threat of Chinese Regional Missiles and U.S.-Allied Missile Defense Response,” Asian Security, Vol. 17, No. 1 (2021); Jaganath Sankaran, “Missile Defenses and Strategic Stability in Asia: Evidence From Simulations,” Journal of East Asian Studies,
Vol. 20, No. 3 (November 2020): 485-508.

12. Gordon Lubold, “Saudi Arabia Pleads for Missile-Defense Resupply as Its Arsenal Runs Low,” The Wall Street Journal, December 7, 2021. See also Ben Hubbard, Palko Karasz, and Stanley Reed, “Two Major Saudi Oil Installations Hit by Drone Strike, and U.S. Blames Iran,” The New York Times, September 14, 2019.

13. See Gordon, “Saudi Arabia Pleads for Missile-Defense Resupply as Its Arsenal Runs Low.”

14. Meg Wagner et al., “Trump Orders New Iran Sanctions After Saudi Attack,” CNN, September 18, 2019, https://www.cnn.com/middleeast/live-news/trump-iran-sanctions-saudi-oil-attack/h_1c5f6b900fad932e5318dac5979b753b.

15. Justin Doubleday, “Ballistic Missile Defense Program Costs Rise to $164.9 Billion,” Inside the Pentagon, August 10, 2017.

16. Ronald O’Rourke, “Navy Aegis Ballistic Missile Defense (BMD) Program: Background and Issues for Congress,” CRS Report, RL33745, April 1, 2022, p. 12.

17. Megan Eckstein, “MDA to Use Destroyer USS John Finn for Defense-of-Hawaii Missile Intercept Test,” USNI News, August 5, 2020, https://news.usni.org/2020/08/05/mda-to-use-destroyer-uss-john-finn-for-defense-of-hawaii-missile-intercept-test; O’Rourke, “Navy Aegis Ballistic Missile Defense (BMD) Program,” p. 12.

18. Anthony Capaccio, “U.S. Navy Ships Close to Getting Interceptors That Could Stop an ICBM,” Bloomberg, June 22, 2021, https://www.bloomberg.com/news/articles/2021-06-22/navy-ships-close-to-getting-interceptors-that-could-stop-an-icbm#xj4y7vzkg.

19. Jason Sherman, “Navy Determines SPY-6 Radar Three Times Stronger Than Original Requirement,” Inside Defense, May 3, 2019.

20. Ibid.

21. Jen Judson, “Missile Defense Agency Director Lays Out Hurdles in Path to Layered Homeland Missile Defense,” Defense News, August 18, 2020, https://www.defensenews.com/digital-show-dailies/2020/08/18/missile-defense-agency-director-lays-out-hurdles-in-path-to-layered-homeland-missile-defense/. See also U.S. Department of Defense, “Layered Homeland Missile Defense: A Strategy for Defending the United States,” n.d., https://media.defense.gov/2020/Jun/22/2002319425/-1/-1/1/LAYERED-HOMELAND-MISSILE-DEFENSE-FINAL.PDF.

22. In addition to these midcourse and terminal defenses, the U.S. Missile Defense Agency has developed and tested a variety of boost-phase missile defenses. See Jaganath Sankaran and Steve Fetter, “Defending the United States: Revisiting National Missile Defense Against North Korea,” International Security, Vol. 46, No. 3 (Winter 2021): 51-86; Jaganath Sankaran and Steve Fetter, “Reexamining Homeland Missile Defense Against North Korea,” The Washington Quarterly, Vol. 43, No. 3 (Fall 2020).

23. Sankaran and Fetter, “Defending the United States.”

24. Lawrence Freedman, US Intelligence and the Soviet Strategic Threat, 2nd ed. (Princeton: Princeton University Press, 1986), p. 96 (citing press conference of U.S. Secretary of Defense Robert McNamara on April 3, 1967).

25. U.S. Department of Defense, “2022 Nuclear Posture Review,” October 27, 2022, p. 4, https://media.defense.gov/2022/Oct/27/2003103845/-1/-1/1/2022-NATIONAL-DEFENSE-STRATEGY-NPR-MDR.PDF#page=40.

Jaganath Sankaran is an assistant professor at the Lyndon B. Johnson School of Public Affairs and a nonresident fellow at the Brookings Institution.



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