May 2025

In addition to domestic upheaval, U.S. President Donald Trump has unleashed what could prove to be a major geopolitical realignment since returning to the White House in January. After 80 years in which the United States led the NATO alliance in setting the terms for international economic management and security, Trump has disparaged allies and shown an unabashed preference for Russian President Vladimir Putin, whom Washington has long viewed as its primary strategic nuclear-armed competitor. Trump has backed Russia at the UN Security Council, blamed Kyiv rather than Moscow for the war in Ukraine, cancelled U.S. membership in various international organizations and hinted he may abandon the U.S. military command of NATO. This radical disruption is raising profound questions about future global nuclear security arrangements and forcing key U.S. allies to prepare for a day in which the United States may no longer be a partner, much less a trusted protector. Arms Control Today asked experts Adam Scheinman, Ulrich Kühn, and Toby Dalton to begin exploring the impact of Trump’s pivot to Russia, respectively, on the nuclear Nonproliferation Treaty and the New Strategic Arms Reduction Treaty; the possibility of Europe developing an independent nuclear deterrent; and the possibility of a security shake-up in Asia.—CAROL GIACOMO

A Stress Test for the NPT
By Adam Scheinman

Is Europe Moving to an Independent Nuclear Deterrent?
By Ulrich Kühn

How Trump’s Turn Toward Putin Could Shake Up Asia
By Toby Dalton

May 2025
By Adam Scheinman

The global nuclear Nonproliferation Treaty (NPT), negotiated in the 1960s with U.S. and Soviet backing and coordination, and extended indefinitely several years after the Cold War collapsed, is among the most significant achievements of the post-World War II period. Absent an NPT, nuclear weapons almost certainly would have spread more widely, international regimes governing nuclear-energy use may never have emerged, and the now 80-year record of nuclear weapons nonuse may not have held for as long as it has.

But can the treaty and the nonproliferation system continue to hold? Even before U.S. President Donald Trump’s election in November, the NPT was coping with the stresses of a rapidly changing global security environment, punctuated by Russia’s illegal full-scale war in Ukraine and China’s growing military power and race to nuclear parity with Russia and the United States. Post-election, those stresses are certain to intensify, especially for the NPT states most vulnerable to nuclear or military aggression.

Given the stakes for global safety and security, defenders of the NPT will need to insulate the treaty and shore up support. If approached as a utilitarian exercise, that is, by aiming to maximize NPT benefits and minimize nuclear risks, treaty parties may yet find it possible to protect the nonproliferation system, even with the tide seeming to be running against it.

Rising Pressures

Making confident predictions about the impact of Trump’s policies on the NPT is challenging, to say the least. This is due in part to his personalist and transactional style, but equally because the new administration has yet to articulate a strategic direction apart from tariff policy and a default to “America First,” which seems more slogan than grand strategy. Uncertainties notwithstanding, there are nonproliferation impacts that bear close watching, including with respect to the nuclear defense of allies, the future course of Iran’s nuclear program, and prospects for arms control.

To be sure, the NPT is not without its defects. Not all nuclear weapon possessors are parties to the treaty and the track record for enforcing compliance, as seen in the cases of Iran and North Korea, is not entirely inspiring. Nor is the NPT immune from deep disagreements among parties on core treaty priorities and obligations, particularly the issue of nuclear disarmament. But those disagreements are largely political and do not threaten the NPT’s future or viability in the way that Russia’s illegal invasion of Ukraine and its ambition to replace the international rules-based order with one organized along spheres of influence could. Regrettably, Trump’s seeming sympathy for this Russian ambition may signal not only a loss of historic U.S. leadership in the NPT, but also a non-trivial risk of states opting for nuclear weapons,¹ or positioning themselves to acquire such weapons quickly, if the NPT or the United States fail to deliver security from nuclear threats or military aggression.

The warning signs are already flashing red. Trump’s decision to negotiate a ceasefire with Russia over the head of Ukraine’s leaders has clearly unnerved allies who rely on U.S. extended nuclear deterrence. In Europe, the credibility of that deterrence rests not only on a small number of U.S. air-delivered nuclear weapons forward-based in several NATO countries, but a shared understanding that any nuclear war in Europe may well escalate to employment of U.S. strategic nuclear forces. Who in Europe, especially states on Russia’s frontier, perceives such unity of commitment today? Recent discussions on options for a “Euro-deterrent”² are an indication that many do not.

Despite U.S efforts across multiple administrations to deepen extended nuclear deterrence commitments, it is not a stretch to imagine Japan or South Korea also opting for independent national nuclear weapons programs if their publics lose faith in U.S. nuclear guarantees to deter China and North Korea, which are rapidly expanding their nuclear weapons and missile forces. The military case in Seoul or Tokyo for proliferation will naturally strengthen if the credibility of U.S. nuclear deterrence is in doubt.

Because China does not wish to see NATO’s nuclear sharing arrangements replicated in Asia, it uses the NPT review process to amplify the false claim that the treaty does not allow for such arrangements.³ China has proven adept at using this issue to embarrass U.S. allies and exploit disarmament frustrations shared by many in the Global South. Notwithstanding the obvious contradictions given China’s increasing reliance on nuclear weapons, it should be anticipated that Beijing will keep this issue high on the NPT agenda considering Trump’s obvious discomfort with alliances.

A more immediate threat to the NPT is the future direction of Iran’s nuclear program. A decision by Iran to leave the treaty could trigger a crisis if Saudi Arabia, Egypt, and perhaps others follow Iran out the door on the grounds that the treaty no longer works for them. Moreover, the prospect of an Iranian nuclear breakout may invite Israeli or U.S. military preemption, which in turn would generate risks of a regional war. Adding greater urgency, Iran’s breakout time to develop a deliverable nuclear weapon has dropped precipitously since 2018 when Trump pulled the United States out of the 2015 nuclear deal known as the Joint Comprehensive Plan of Action.

This year will be critical for the Iran nuclear issue, and therefore for the NPT. In February, Trump signed a national security memorandum restoring “maximum pressure” on Iran; more recently, he announced support for a diplomatic resolution if it can prevent Iran from acquiring a nuclear weapon. Given recent setbacks to Iran’s security position in the region, Tehran presumably has an incentive to explore a bargain. For his part, Trump will not be burdened with opposition in the Republican-controlled Congress as President Barack Obama was in 2015. With full international sanctions set to “snap back” on Iran in October, the clock on a solution is ticking.⁴

Stabilizing the NPT

The second Trump administration inherits an NPT regime that is working but faces significant headwinds. Beyond familiar disagreements on disarmament or a Middle Eastern WMD-free zone (which for some parties is a proxy to pressure Israel), Russia’s war in Ukraine and its grossly negligent nuclear conduct—from threats of nuclear-weapons use to its armed seizure of a Ukrainian nuclear power plant—collapsed all forms of cooperation between Russia and West. Notably, this has included a political level dialogue among the treaty’s five recognized nuclear-weapon states (China, France, Russia, the United Kingdom, and the United States) to coordinate on NPT matters. It would be preferable if the five states returned to dialogue and cooperation on the NPT, but this likely remains out of reach absent a settlement in Ukraine.

In the interim, the window is open for other leading NPT voices to advance an agenda to stabilize the treaty and encourage future dialogues and agreements. This “stabilizers” group should include states from across the political spectrum that are willing to set aside narrow political agendas and keep focus on the NPT’s higher purpose, which as stated in its first preambular paragraph is to avert the “devastation that would be visited upon all mankind by a nuclear war.”

Taking this as direction, the group should give priority to a range of nuclear arms control and risk reduction measures that, while not new to the NPT process, are urgently needed. This could include a U.S.-Russian agreement to hold to the New Strategic Arms Reduction Treaty numerical caps and restore verification until a new deal with China and Russia, which Trump has said he favors,⁵ can be discussed.

This approach also could cover confidence-building measures to limit risks of inadvertent military escalation, such as agreements on transparency and crisis management and prevention, as well as restraints on nuclear weapons testing and fissile material production. The five nuclear-weapon states, for instance, could commit collectively not to be the first to resume nuclear testing and to address concerns surrounding activities at nuclear test sites, which is the minimum necessary for U.S. ratification of the Comprehensive Test Ban Treaty. They also could consider alternative frameworks to the Conference on Disarmament for agreement among all nuclear possessor states to cut off production of fissile material for weapons use.

Realistically, the scope for agreement even on this agenda is narrow and contingent on much falling the right way, such as avoiding a U.S. break with allies over trade or defense or the renewal of open-ended nuclear arms racing. In addition, there is simply not sufficient time to make much progress on a “stabilizer” program between now and the 2026 NPT Review Conference. Rather than overload the circuits, the state-parties instead could set goals in 2026 to be assessed or updated in 2030.

To broaden support and enhance credibility, a program of stabilizing the NPT would need to extend to all aspects of the treaty, including a commitment of the advanced economies to facilitate the anticipated expansion of peaceful nuclear energy and science. With new, more affordable, small modular reactor designs ready to hit the market, this is the time to ensure that the transition to nuclear energy meets the highest standards for nuclear nonproliferation, safety and security. Given that all five NPT-recognized nuclear-weapon states are major nuclear suppliers and share an interest in preventing new proliferation, coordination on this topic also could be expected if and when the governments are ready to resume their political-level dialogue.

Skeptics of this overall approach will argue that it lacks ambition or represents a step back from prior commitments relating to nuclear disarmament. In fact, progress on a stability agenda would be a step back from the brink and a return to principles and practices of nuclear restraint. Given the stakes, states should be encouraged to set aside disarmament theology and approach the NPT from a utilitarian perspective, aiming to reduce nuclear weapons dangers at a time of transition in the global order. Knowing from history that not all such global transitions ended peacefully, one can only hope that the treaty’s leading members are up to the task.

ENDNOTES

1. Ankit Panda, Vipin Narang, and Pranay Vaddi, “Nuclear Proliferation Will Haunt ‘America First,’” War on the Rocks, March 10, 2025.

2. Ankit Panda, “France, UK must heed the call of Europe’s new nuclear age,” Defense One, March 20, 2025.

3. William Alberque, “The NPT and origins of NATO’s nuclear sharing arrangements,” Institut Francais des Relations Internationales, Proliferation Papers, No. 57 (February 2017).

4. Michelle Nichols, “Explainer: How UN sanctions on Iran could be restored,” Reuters, April 10, 2025.

Adam Scheinman was the special representative of the president for nuclear nonproliferation, with the rank of ambassador, in the Biden and Obama administrations.

May 2025
By Ulrich Kühn

Europe is in turmoil. Polish Prime Minister Donald Tusk is calling for his country to “reach for the most modern capabilities also related to nuclear weapons.”¹ The incoming German chancellor, Friedrich Merz, finds that, “We need to have discussions with both the British and the French … about whether nuclear sharing, or at least nuclear security from the UK and France, could also apply to us.”² In turn, French President Emmanuel Macron is ready to “open this discussion … if it allows to build a European force.”³ At the same time, the European Union Commission is suggesting a $900 billion package to “rearm Europe” with the latest weaponry while Germany has signaled that it could start spending more than $450 billion on defense. Not since the Cold War years have Europeans felt so threatened. Many wonder whether Europe and the United States are still allies.⁴

All this is the result of two men’s ambitions. The one sitting in the Kremlin, Russian President Vladimir Putin, is waging the bloodiest land war on European soil since the guns of World War II fell silent. The other one, U.S. President Donald Trump, re-entered the White House having  pledged to end Russia’s full-scale war in Ukraine “within 24 hours.”⁵ His tactics include cozying up to Moscow, pressuring Kyiv into submission, and sidelining European allies. Putin turned up the heat in 2022 and Trump closed the lid three years later. Europe is a pressure cooker, and the temperature is quickly rising.

Frantic calls for European nuclear deterrence are hardly new. They were a constant background noise to Trump’s first four years as president,⁶ but this time is different. There is now a profound sense among Europeans that “Donald Trump will no longer uphold NATO’s mutual defense commitment unconditionally,” as Merz put it.⁷ Breaking with his predecessors, Merz is openly courting Macron, who for years had offered Europe-wide discussions on the role of French nuclear forces in European security. Another difference: Germany now brings the resources and willingness to invest serious money in defense. Some officials in Berlin have already hinted at German co-sponsorship of the French arsenal.⁸

Underlying all of this is an acute feeling that time is running out—that this is Europe’s last chance to stand on its own feet militarily; that Ukraine’s fate may ultimately hinge on European determination to help prevent a full Russian victory; that soon, the United States might not only turn away, but turn against Europe. Lately, some commentators have started to warn that this summer could be the last that Europeans enjoy peace.⁹ Yet, would a new nuclear weapons arrangement really make Europeans safer?

Deterring What?

What should European nuclear deterrence deter? The two most prominent answers to that question are a Russian land grab in Eastern Europe and Russian nuclear blackmail.¹⁰ The latter is based on an ambiguous reading of recent evidence. On the one hand, Russia has constantly sought to manipulate Ukraine’s military supporters with its hostile nuclear rhetoric.¹¹ The result is mixed.¹² Yes, Moscow has slowed Western military support to Kyiv, sometimes significantly, and prevented more forceful responses, such as a no-fly zone over Ukraine. Yet, the Kremlin has not stopped the steady flow of military hardware, including weapons that could strike deep into Russian territory.

Russian nuclear blackmail against Ukraine has been even less successful. Kyiv has continued its fight for survival no matter what Moscow has threatened, even invading a part of Russia. The war’s empirics corroborate nuclear scholarship, which has found that nuclear blackmail is rarely successful¹³ and that nuclear deterrence against non-nuclear attackers may even have no effect.¹⁴ As such, the nuclear blackmail justification for European nuclear deterrence is rather shaky.

The land-grab argument seems more convincing. Accordingly, Russia could seek to invade a part of Eastern Europe—given the favorable geography, most likely in the Baltic states—to satisfy its ambitions or to expose the Europeans as weak, thereby positioning itself as Europe’s preeminent power.¹⁵ To be successful, Russian conventional forces would have to quickly overwhelm Baltic defenses while Russian nuclear forces would shield the invasion, forcing Europeans who rush to defend the Baltic states to back down.

In a world where U.S. nuclear forces might no longer serve as a backstop to European security, Russia could conclude that nuclear threats against the rest of Europe could help achieve a military fait accompli. The fact that Russia continues to respect NATO territory as a sanctuary in its war against Ukraine could certainly lead to the conclusion that Russia respects nuclear deterrence, and that Europeans would need nuclear weapons to deter future contingencies in the Baltic states. Yet the bigger takeaway could be that future deterrence in Eastern Europe should focus on conventional forces that make any Russian land grab impossible in the first place.

One scenario that is rarely discussed openly is that Europeans may need their own nuclear deterrent to deter the United States. Trump’s musings that “the world needs us to have Greenland”¹⁶ either through a financial deal or by military force provides the right context to start thinking about the unthinkable.

Since none of the arguments sound entirely plausible, it is possible that Europeans are discussing the nuclear option out of a mix of sheer panic and habit. As an example, Germans have been living under U.S. nuclear protection for some 70 years and successive German governments have chosen regularly to stick to this arrangement.¹⁷ For two decades until 2022, when no one needed U.S. nuclear weapons in Germany, the German public wanted to get rid of these weapons. When Russia invaded Ukraine and threatened Germany, the mood suddenly shifted.¹⁸ Now that Trump is threatening to leave Europe, a majority of Germans want the creation of a European nuclear deterrent.¹⁹ A radical alternative would be for Germans to think about their own security in purely non-nuclear terms. Quite understandably that may be a habitual and psychological stretch too far for most Europeans, particularly in the middle of a major war.

Deterring How?

If the non-nuclear option is too radical, what could a European nuclear deterrent look like? It certainly will not be a supranational EU mechanism but instead will rely on the independent nuclear forces of France and, perhaps, the United Kingdom. Both countries will insist on having the final say, at least when it comes to weapons employment. There would be another no-go as well: Despite Europe’s promised defense spending spree, a European nuclear deterrent will not replicate the U.S. extended deterrence model. Doing so probably would overwhelm European financial resources. The Europeans also are unlikely to seek to match Russian nuclear capabilities. Europe does not need thousands of strategic and tactical nuclear arms. It also cannot afford a full-fledged nuclear sharing arrangement entirely based on non-U.S. assets, at least not now.

Yet, there are steps that Europeans can start taking, such as deepening French-UK cooperation, allowing France regular use of allied European airfields, undertaking explicit public deterrence messaging by prominent European politicians, and perhaps even soliciting financial support from a European coalition of the willing.²⁰ Over the medium term if necessary, France could consider a small increase in its air-delivered munitions and possible French nuclear deployments to other European countries. The UK may think about reinstating its air-delivered nuclear component while seeking more independence from the United States for its nuclear program. All that would give France and the UK more escalation options against Russia and send reassuring signals to jittery allies in Eastern Europe.

Negative Consequences

There are undoubtedly downsides to European nuclear deterrence. It is expensive and will become even more so when extended to others. France just rushed to reopen a fourth nuclear airbase in response to Trump for $1.7 billion.²¹ Paris will soon feel the same pressure that Washington dealt with throughout the Cold War—namely, allies that constantly demand reassurance while never feeling fully reassured. Russia could exploit this effect, pushing Europeans into spending more and more on nuclear arms.

That is why conventional deterrence matters so much. It is the most cost-effective and credible way to contain Russia. It also could have the beneficial effect of bolstering Europe’s defense industry and making Europeans less dependent on U.S. military gear.

Establishing a credible European nuclear deterrent will deliver a severe blow to the global nonproliferation regime. Member states of the nuclear Non-Proliferation Treaty (NPT) would rightfully question whether any move to extend French and UK nuclear deterrence to Europe would be in line with the treaty. Despite the argument brought forward by German legal experts that financial support for French nuclear forces would not violate the NPT,²² politically, any such move could well mean the treaty’s death knell.

For that reason, Europeans would be well advised to complement deterrence with arms control. An arms control track could focus on conventional confidence-building measures along Europe’s long border with Russia and, over the medium term, possible limits on certain kinds of stand-off weapons most prone to cause crisis instability. The biggest obstacle to a purely European arms control approach could be Russia. For many years, the Kremlin has seemed hard-pressed to accept Europeans as independent security actors.

Whether Washington really will turn from protector to predator, and what that could mean for U.S. security guarantees to Europe, including the nuclear ones, remains to be seen. Ultimately, U.S. behavior will decide how far and how fast Europeans may go down the route of nuclear independence. All of this is more than deplorable from a nonproliferation perspective. At some point, however, a European nuclear deterrent could well be seen as the lesser evil. What if the French far right wins the presidential election in two years and declares a “France first” policy? No one should exclude anything at this stage of uncertainty in Europe, including a German or a Polish bomb.

ENDNOTES

1. Jan Cienski and Wojciech Kość, “Poland seeks access to nuclear arms and looks to build half-million-man army,” Politico, March 7, 2025.

2. Chris Lunday, “Europe should brace for Trump to end NATO protection, Germany’s Merz warns,” Politico, February 21, 2025.

3. “France’s Macron is ready to discuss nuclear deterrence for Europe,” Reuters, March 1, 2025.

4. Lauren Sukin, Michal Smetana, Marek Vranka, and Ondrej Rosendorf, “Are the United States and Europe still allies? The European public doesn’t think so,” Bulletin of the Atomic Scientists, March 26, 2025.

5. Julia Mueller, “Trump says he would ‘solve’ war in Ukraine in 24 hours if reelected,” The Hill, March 28, 2023.

6. Tristan Volpe and Ulrich Kühn, “Germany’s Nuclear Education: Why a Few Elites Are Testing a Taboo,” The Washington Quarterly, Vol. 40, No. 3 (2017): pp. 7-27.

7. Lunday, February 21, 2025.

8. Christian Lindner, “Europa muss an nuklearer Abschreckung festhalten [Europe Must Maintain Nuclear Deterrence],” Frankfurter Allgemeine Zeitung, February 13, 2024.

9. Iryna Nesterova, “The last peaceful summer in Europe: a German historian made an alarming prediction – BILD,” Ukraine Today, March 23, 2025.

10. Both arguments have been repeated in the German media for more than a year, for example, including by prominent politicians such as German Defense Minister Boris Pistorius; see Nicolas Camut, “Putin could attack NATO in ‘5 to 8 years,’ German defense minister warns,” Politico, January 19, 2024.

11. Ulrich Kühn, “The Fall Crisis of 2022: why did Russia not use nuclear arms?” Defense & Security Analysis, (2024, ahead of print): pp. 1-21.

12. Janice G. Stein, “Escalation Management in Ukraine: ‘Learning by Doing’ in Response to the ‘Threat that Leaves Something to Chance,’” Texas National Security Review, Vol. 6, No. 3 (2023): pp. 29-50.

13. Todd S. Sechser and Matthew Fuhrmann, Nuclear Weapons and Coercive Diplomacy (Cambridge, UK: Cambridge University Press, 2017).

14. Daniel S. Geller, “Nuclear Weapons, Deterrence, and Crisis Escalation,” Journal of Conflict Resolution, Vol. 34, No. 2 (1990): pp. 291-310.

15. Manuel Bewarder and Florian Flade, “Bereitet Russland einen Angriff auf die NATO vor? [Is Russia Preparing an Attack on NATO?],” Tagesschau, March 27, 2025.

16. David Brennan, “Trump says US will ‘go as far as we have to’ to get control of Greenland,” ABC News, March 27, 2025.

17. Ulrich Kühn, “Of Dependence and Conservatism: Conclusions for German Nuclear Policies in the 21st Century,” in Ulrich Kühn (ed.), Germany and Nuclear Weapons in the 21st Century: Atomic Zeitenwende? (London and New York: Routledge, 2024): pp. 302-314.

18. Michal Onderco, “German Public Opinion on Nuclear Weapons Before and After Russia’s Invasion of Ukraine,” in Kühn, Germany and Nuclear Weapons in the 21st Century, pp. 136-154.

19. Joseph de Weck and Shahin Vallée, “Germans Back Merz’ ‘Whatever It Takes’ on Debt and Defense,” Internationale Politik Quarterly, No. 3 (2025).

20. Héloïse Fayet, Andrew Futter, Ulrich Kühn, Łukasz Kulesa, Paul van Hooft, and Kristin Ven Bruusgaard, “Forum: European Nuclear Deterrence and Donald Trump,” Survival, Vol. 67, No. 1 (2025): pp. 123-142.

21. Laura Kayali, “France to reopen fourth nuclear air base as Europe rushes to rearm,” Politico, March 18, 2025.

May 2025
By Toby Dalton

The about-face on Russia by U.S. President Donald Trump’s administration, amplified by its sharp criticism of the United States’ European allies and apparent abandonment of Ukraine, is scrambling the security order in Europe. Yet, the broader significance of Trump’s embrace of Russian President Vladimir Putin and shift away from enduring interest-based alliances is that these moves also could portend considerable disruption in Asia. Some of that disruption might be positive, for example if it leads to arms control talks with China or a nuclear restraint agreement with North Korea. Yet, it also could drive South Korea or Japan to acquire nuclear weapons if they feel abandoned by the United States.

Russia vs. China

Trump’s shift toward Russia reads like a classic great-power politics gambit: an attempt to ameliorate conflict between Washington and Moscow that otherwise keeps the United States tied to Europe, and to woo Russia over to the U.S. side against China.

The biggest unknown is whether Putin sees the situation reciprocally. In recent years, Russia pursued a comprehensive strategic relationship with China, what the two countries have labeled a “no limits” partnership.¹ In the three years since Russia’s full-scale invasion of Ukraine, Beijing and Moscow have deepened their military ties and now regularly conduct combined exercises. China has been a steadfast although primarily rhetorical supporter of Russia’s war in Ukraine, and the two countries are aligned in challenging or subverting a U.S.-led international order. Broadly, the ideological divisions and divergent interests that contributed to the Sino-Soviet split in the 1960s are not present today and it seems doubtful that the United States could easily drive China and Russia apart.

If creating a wedge between China and Russia proves impossible, Trump may instead seek Putin’s help to engage Chinese President Xi Jinping in nuclear talks. Although perhaps not as strong as his obsession with striking a nuclear deal with North Korea, Trump periodically floats the idea of China joining Russia-U.S. nuclear arms control negotiations. He stated March 6, “I was very close to having a program with Russia—denuclearization—and we were going to get China; I spoke with President Xi about it, and he would have been very happy to go along with it.… But I would very much like to start those talks … the denuclearization would be incredible.”²

Despite Trump’s bromides, China’s consistent position on joining arms control negotiations effectively can be summarized as “No thanks; you first make deeper cuts and then we might consider it.”³ Yet, a Russia-U.S. rapprochement that facilitates a successor to the New Strategic Arms Reduction Treaty eventually could enable three-way talks with China. Although it is difficult today to imagine such an agreement to limit or even reduce nuclear arms, there are many other avenues for reducing the chances of nuclear use that would be beneficial for U.S. and global security.

Russia, North Korea, and Nuclear Talks

To help prosecute its war in Ukraine, Russia revamped its military relationships with North Korea and Iran. Initially, this involved buying Iranian-made kamikaze drones and North Korean artillery shells. Later, North Korea provided short-range ballistic missiles and even 11,000 soldiers to fight directly alongside Russian forces seeking to expel Ukrainian forces from occupied territory in Russia’s Kursk region. North Korea and Russia signed a new mutual defense pact in June 2024.

The quid pro quos for this military assistance to Russia are not fully clear, although Russia promised to cooperate on space and peaceful nuclear energy with North Korea as part of upgraded military ties. More broadly, analysts have interpreted Russia’s embrace of both countries—North Korea has tested a nuclear weapon and Iran is moving closer to being able to produce a bomb—as indicating abandonment of nonproliferation as a long-standing strategic priority. U.S. officials warned in December 2024, for example, that “Russia may be close to accepting North Korea’s nuclear weapons program, reversing Moscow’s decades-long commitment to denuclearize the Korean peninsula.”⁴

How Russia treats these partnerships in the future could be a critical factor as Trump seeks to forge a broader rapprochement with Putin, and also to constrain the nuclear programs of Iran and North Korea. Does Putin see them as transient relationships of convenience in the context of Ukraine or as building blocks of Russia’s effort to reconstitute its global power?

To that point, in a March 18 telephone call that raised more questions than answers, Trump and Putin reportedly agreed on “the need to stop proliferation of strategic weapons and [to] engage with others to ensure the broadest possible application.”⁵

North Korea poses the most challenging issues in this regard. Trump regularly expresses interest in rekindling efforts to reach a nuclear deal with North Korean leader Kim Jong Un, as he did March 13, saying, “I have a great relationship with Kim Jong Un, and we’ll see what happens, but certainly he’s a nuclear power.”⁶ North Korea’s nuclear weapons arsenal has indeed grown in number and sophistication since Trump failed to close a restraint agreement with Kim during their summit diplomacy in 2018-2019. These advanced North Korean capabilities are among the drivers of South Korean interest in nuclear weapons, so a restraint agreement with Pyongyang could also dampen nuclear clambering in Seoul.

As with Xi, Putin might be tempted to parlay Trump’s desire for a nuclear deal with Kim for a seat at the negotiating table and influence on the outcome. Undoubtedly, Putin would want to ensure that any North Korean-U.S. engagement does not compromise Russian interests, but he also may calculate that helping Trump could yield dividends elsewhere.

Conversely, North Korea may be perceived in Russia as a useful thorn in the side of the United States and its Asian allies. Russian national security expert Dmitry Trenin argued in 2023, for example, that, “destabilization of the [nuclear Nonproliferation Treaty] is an important factor undermining American hegemony.… [T]he DPRK and Iran are political opponents of the United States and at the same time increasingly close partners of Russia. It is unthinkable to cooperate with Washington, which is waging a war with Russia by the hands of Ukrainians, against Iran and the DPRK, which somehow help [sic] us in this war.”⁷

Impact on Japan and South Korea

Thus far, Japan and South Korea have been spared the ire of Trump administration officials, who mainly have criticized European governments for various perceived offenses. But Seoul and Tokyo no doubt are discomfited by Trump’s intimations that he may not feel bound by long-standing U.S. security guarantees. During the 2024 presidential campaign, for instance, Trump famously recounted a conversation with a foreign head of government in which he said he “would not protect you. In fact, I would encourage [Russia] to do whatever the hell they want. You gotta pay.”⁸ In this regard, Trump’s abusive abandonment of Ukraine could spur additional efforts to augment security capabilities, including consideration of nuclear weapons, among U.S. Asian allies. South Koreans, in particular, have long harbored fear about U.S. abandonment dating to the 1949 withdrawal of U.S. military personnel, followed shortly thereafter by the North Korean invasion that catalyzed the 1950-1953 Korean War.

In Seoul, there has been growing interest in and public support for nuclear weapons for over a decade, well before Trump was even a likely political candidate. South Korean political conservatives are the most vocal champions of a domestic nuclear weapons program, but Trump’s behavior may give progressives reason to reconsider their skepticism. For now, there is a growing movement for nuclear “latency” (called the Mugunghwa Forum), whereby South Korea would accumulate the additional capabilities necessary for producing nuclear weapons should it decide to build them in the future.⁹

Nuclear latency advocates are urging the South Korean government to negotiate with the United States for permission to develop uranium enrichment and plutonium reprocessing capabilities, first by upgrading the existing South Korean-U.S. nuclear cooperation agreement. This is highly likely to be a key item on Seoul’s wish list as South Korean and U.S. officials sort through alliance, security, and trade issues.

The real wild card pertains to the Trump administration’s intentions regarding the U.S. defense posture and extended deterrence commitments. If Trump seeks to withdraw U.S. forces stationed on the Korean peninsula, then South Korean leaders might feel forced to proceed with a nuclear weapons effort, despite the challenges they would likely encounter.

Japan in many ways occupies a more difficult position: With a capable but constrained self-defense force, it is more reliant on U.S. extended deterrence despite its security and territorial issues with China, North Korea, and Russia. Tokyo has fewer immediate options to remedy U.S. retrenchment, apart from building nuclear weapons, which it likely could achieve faster than South Korea but which would be far more politically complicated given the strong Japanese pro-disarmament movement. Tokyo seems likely to continue efforts to stay out of Trump’s firing line and not give him any reason to consider abandonment.

As the implications of Trump’s shift toward Russia become clear, the potential effects in Asia seem likely to boil down to the issue of linkage. In the past, Russia has proved willing to use its influence to further nonproliferation goals, as it did during negotiations with Iran leading to the 2015 nuclear agreement. However, if transactional politics dominate in the absence of a broader Russian-U.S. strategic alignment, Moscow will be less willing to use its influence with China or North Korea in ways that could benefit the United States.¹⁰ At least, not without extracting a price. Whether that price includes a reduction in the U.S. defense posture in Asia, negotiated without the input of U.S. allies, will be a critical determinant of the future number of nuclear-armed states in the region.

ENDNOTES

1. “Joint Statement of the Russian Federation and the People’s Republic of China on the International Relations Entering a New Era and the Global Sustainable Development,” President of Russia, February 4, 2022.

2. @RapidResponse47, Remarks by U.S. President Donald Trump, X, March 6, 2025, 3:13 PM.

3. “Foreign Ministry Spokesperson Guo Jiakun’s Regular Press Conference on February 14, 2025,” Ministry of Foreign Affairs of the People’s Republic of China, February 14, 2025.

4. “Remarks by Ambassador Linda Thomas-Greenfield at a UN Security Council Briefing on Nonproliferation and the Democratic People’s Republic of Korea,” United States Mission to the United Nations, December 18, 2024.

5. White House Press Secretary Karoline Leavitt, “President Donald J. Trump’s Call with President Vladimir Putin,” U.S. Embassy & Consulates in Russia, March 18, 2025.

6. “Trump says he still has good relations with leader of ‘nuclear power’ North Korea,” Reuters, March 13, 2025.

7. Dmitry Trenin, “On a New Global Order and Its Nuclear Dimension. An Interview,” PIR Center, 2023, No. 2: 36, 2023.

8. Jill Colvin, “Trump says he once told a NATO ally to pay its share or he’d ‘encourage’ Russia to do what it wanted,” Associated Press, February 11, 2024.

9. Lami Kim, “South Korea’s Nuclear Latency Dilemma,” War on the Rocks, September 19, 2024.

10. Keith Bradsher and Berry Wang, “China Backs Iran in Nuclear Talks, Slams ‘Threat of Force’ From the West,” The New York Times, March 14, 2025.

May 2025
By Kelsey Davenport

The United States and Iran began discussions on a nuclear agreement, but Trump administration officials have sent mixed messages about U.S. objectives for a deal. Specifically, it is unclear if the United States will accept an agreement that allows Iran to continue to enrich uranium, an issue that Iran says is non-negotiable.

President Donald Trump told reporters that the United States and Iran would begin negotiations in Oman the following week during an April 6 meeting with Israeli Prime Minister Benjamin Netanyahu. The New York Times reported on April 16 that Trump told Netanyahu during the meeting that the United States would not support Israeli plans to strike Iran’s nuclear program in May. Trump told reporters on April 17 that he is not “in a rush” to attack and that Iran is “wanting to talk.”

Although both Trump and Iranian President Masoud Pezeshkian have expressed support for a nuclear deal, it is unclear if the two sides will be able to bridge the gaps and reach an agreement. Netanyahu also appears unlikely to support an agreement. He released a video statement on April 7 suggesting that Israel would support diplomacy with Iran, but an effective agreement must include completely dismantling Iran’s nuclear program under U.S. supervision.

The United States and Iran described the first meeting between U.S. Special Envoy to the Middle East Steve Witkoff and Iranian Foreign Minister Abbas Araghchi as constructive. Although the talks were indirect, Araghchi and Witkoff shook hands and spoke briefly.

After the meeting, Witkoff told Fox News April 14 that Iran could enrich uranium up to 3.67 percent uranium-235, a level suitable for nuclear reactor fuel. He also said a deal would focus on monitoring and prohibiting weaponization-related activities. The following day, however, Witkoff said on X that Iran must “eliminate its nuclear enrichment and weaponization program.”

Other senior Trump administration officials, including Secretary of State Marco Rubio and National Security Advisor Michael Waltz, also suggested Iran must give up uranium enrichment as part of an agreement.

Araghchi told Iranian media April 16 that the shifting U.S. position is “not helpful,” but he said Iran will look to the United States to make clear its “real position” during talks.

He said Iran’s nuclear enrichment program is intended to fuel nuclear power reactors and that Iran is willing to “build trust regarding potential concerns but the issue of enrichment is non-negotiable.”

In a transcript of a speech Araghchi intended to deliver April 21, he elaborated on Iran’s position, saying Tehran is “ready to engage” with Washington, but the basis for talks must include a “recognition of our rights” under the nuclear Nonproliferation Treaty (NPT), “including the ability to produce fuel for our nuclear power plants.”

The United States disagrees that the provision in the NPT that guarantees non-nuclear-weapon states access to nuclear technology under appropriate safeguards for peaceful purposes includes a right to enrich. However, the Obama administration’s acknowledgement that Iran could retain a limited uranium enrichment program was critical for advancing negotiations toward the interim nuclear deal in 2013 and later the 2015 deal, known as the Joint Comprehensive Plan of Action (JCPOA).

Under the JCPOA, Iran agreed to limit its uranium enrichment to a level suitable for reactor grades, 3.67 percent of U-235, the level Witkoff initially suggested the United States could support in a new deal.

Currently, Iran is enriching uranium up to 60 percent, U-235. Sixty percent enriched uranium is near-weapons grade and has no legitimate civilian purpose in Iran’s program.

Despite Witkoff backpedaling on the issue of uranium enrichment, Araghchi said the two parties moved forward during the second round of talks in Rome on April 19 and have a “better understanding of the goals.” He said that Iran is “seeking an agreement as quickly as possible” but noted it will not be easy.

Trump told reporters on Air Force One April 12 that the talks were going “okay” but “nothing matters until you get it done.”

International Atomic Energy Agency Director-General Rafael Mariano Grossi stressed the short timeframe available for talks during an April 15-16 meeting in Tehran. Grossi told reporters April 17 that IAEA verification of any deal is necessary to ensure its validity. He said the IAEA is in contact with the U.S. negotiating team to see how the agency can “help achieve a positive outcome in the negotiations.”

The IAEA has raised concerns in its quarterly reports on Iran’s nuclear program about the challenges of reconstituting credible baseline inventories in certain areas, such as centrifuges, since Iran reduced agency access and monitoring in February 2021.

Grossi said during the second round of talks in Rome in an April 19 X post that cooperation with the IAEA is “indispensable to provide credible assurances about the peaceful nature of Iran’s nuclear programme.”

May 2025
By Xiaodon Liang

U.S. generals are calling for an increase in the number of B-21 nuclear-capable strategic bombers that the United States will buy, lauding the aircraft as a rare on-time and under-budget component of an otherwise increasingly troubled nuclear modernization program.

The Air Force should acquire 145 B-21s instead of a planned 100, said Gen. Anthony J. Cotton, head of U.S. Strategic Command, March 18 at an industry conference. Although he and other commanders have hinted previously at recommending an increase to the B-21 program, this was the first time Cotton has explicitly endorsed a higher target. He repeated the recommendation at a March 26 hearing before the Senate Armed Services Subcommittee on Strategic Forces.

Cotton also reiterated a prior call for an acceleration of the B-21 program, which is in low-rate initial production under the supervision of lead contractor Northrop Grumman. The chief executive of the company, Kathy Warden, said on  a call April 22 that the firm had already made investments to prepare to speed up production rates, bringing company losses on the bomber to an expected $2 billion over the first five years of production.

The House Armed Services Committee voted April 29 to provide $4.5 billion over the next four years to accelerate B-21 production, as part of a broader budget reconciliation bill.

In an exchange with Senator Mike Rounds (R-S.D.) during the March 26 hearing, Cotton said he was concerned about a significant temporary shortfall—a “bathtub” plunge—in the availability of strategic bombers as the B-2 and B-1 fleets age and retire.

Cotton’s recommendation is backed by some high-ranking Air Force officers. The “demand signal for the bombers is greater than any time I’ve seen in my career,” said Gen. Thomas A. Bussiere, head of Air Force Global Strike Command, at a Dec. 5 Mitchell Institute event.

But other Air Force leaders have been more cautious. A year ago, the service’s chief of staff, Gen. David W. Allvin, declined before the Senate Armed Services Committee to commit to an expansion of the program, noting that available technologies may have changed by the time the planned 100-aircraft production run is completed in the mid-2030s.

President Donald Trump’s nominee to serve as secretary of the Air Force, Troy Meink, suggested openness to reassessing the bomber requirement during his March 27 confirmation hearing before the same Senate committee. The Air Force fleet is “probably too small both on the fighter and the bomber sides of the house,” Meink said.

The B-21 program is “a successful acquisition program by all accounts,” according to Michael Duffey, the nominee for undersecretary of defense for acquisition and sustainment, as he testified alongside Meink March 27.

Duffey’s optimistic view is supported by price estimates published in November 2024 by Aviation Week & Space Technology, which said that the cost to the Air Force of the initial five-years of production has fallen 28 percent from $19.1 billion, as estimated in fiscal year 2023, to $13.8 billion in fiscal 2025. The Defense Department withholds more budgetary and programmatic information about the B-21 than most components of the nuclear modernization effort.

Northrop Grumman received its second year-long, low-rate initial production contract in December. Over the first five contracts, the company is set to build 21 initial aircraft under a fixed-price-plus-incentive reimbursement framework (See ACT, January/February 2025.)

The nuclear-tipped, air-launched cruise missile that the B-21 will deliver, the Long Range Stand Off Weapon, underwent a first flight test in January with its W80-4 warhead, which is in development, according to the Exchange Monitor. The W80-4 program has struggled recently with design issues that could impact its production schedule, according to a January performance evaluation report by the National Nuclear Security Administration, which reviewed work by a key contractor at Lawrence Livermore National Laboratories.

The W80-4 program leadership needs a “focused and disciplined approach” to “avoid program schedule impacts” for the warhead, the evaluation report said.

New delays also are affecting Air Force programs to upgrade the aging B-52H strategic bomber to a new B-52J configuration. According to the annual report of the Pentagon’s director of operational test and evaluation, released in January, the B-52 radar modernization program will now enter production in fiscal 2026 at the earliest. A parallel program to replace the planes’ engines will reach an equivalent milestone in fiscal 2029.

The relative success of the B-21 program stands in contrast to continuing problems with the Columbia ballistic missile submarine and the Sentinel intercontinental ballistic missile (ICBM).

The lead ship of the Columbia class is now 12 to 18 months behind schedule, Navy acquisition leaders said in an April 8 statement to the Senate Armed Services Subcommittee on Seapower and Projection Forces. Work on the second boat of the class remains on schedule, the statement says.

Navy efforts to attract more skilled labor to shipyards have had mixed results, with between 50 and 60 percent of new employees leaving their jobs within the first year, said Brett Seidle, the acting assistant secretary of the Navy for research, development, and acquisition, before the same subcommittee March 26.

As the Air Force reevaluates the scope of the Sentinel ICBM program following a Nunn-McCurdy cost-growth review last year, officials also are weighing the steps needed to keep the Minuteman III ICBM in service through 2050, Bloomberg News reported March 27. The Sentinel is now expected to enter service several years after its target date of 2029. (See ACT, September 2024.)

May 2025
By Xiaodon Liang

U.S. President Donald Trump’s nominee to head the National Nuclear Security Administration (NNSA) said he “would not advise testing” nuclear weapons above the criticality threshold.

But the nominee to be administrator, Brandon Williams, testifying at his April 8 Senate Armed Services Committee confirmation hearing, also noted that a decision to resume explosive nuclear testing would be “above [his] pay grade.”

Williams’ comments came in response to questioning by Sen. Jacky Rosen (D-Nev.), who expressed concern that resuming explosive nuclear testing could create “severe economic and environmental impacts.” The Nevada National Security Site, where NNSA conducts subcritical nuclear experiments, almost certainly would host any potential underground explosive test.

Rosen said China and Russia would probably resume explosive nuclear testing if the United States were to test first, and those countries “have more to gain from testing than we do, given our superior scientific and computer-modeling capabilities.”

Williams, a former Navy ballistic-missile submariner and Republican congressman, agreed that explosive testing during the Cold War had provided data to underpin the “scientific basis for confirming the stockpile since the moratorium in 1992.”

Scott Pappano, a Navy vice-admiral nominated to be Williams’ principal deputy at NNSA, also told the same Senate committee April 29 that he “would not advocate for nuclear testing based on the amount of data we have.”

Concerns about a resumption of testing have grown since Robert O’Brien, a national security advisor in Trump’s first term in office, wrote in Foreign Affairs in June that “Washington must test new nuclear weapons for reliability and safety in the real world for the first time since 1992—not just by using computer models.”

During O’Brien’s government tenure, a group of U.S. officials discussed testing in May 2020, according to a report in the Washington Post. (See ACT, June 2020.)

The technical need for testing has been dismissed by officials involved in the U.S. stockpile stewardship program. Marvin Adams, the deputy administrator for defense programs at NNSA under the Biden administration, told reporters on a tour of the Nevada National Security Site Dec. 13 that “based on purely technical considerations, we are confident that we can get the information we need [through] subcritical” experiments and other elements of the stockpile stewardship program.

The 2020 debate considered not only technical arguments, however, but also policy justifications such as intimidating nuclear peers during arms control talks.

A report by the Trump-aligned Heritage Foundation in July called for reducing the time needed to prepare an underground explosive nuclear test to six months. Under a requirement last reaffirmed in 2022 by the Biden administration, the NNSA is required to be ready to conduct a test with limited diagnostics within 36 months.

In September, Russian Deputy Foreign Minister Sergey Ryabkov told news agencies that Russia “will not conduct [supercritical nuclear tests] if the United States refrains from such steps.”