Missiles, Preemption, and the Risk of Nuclear War on the Korean Peninsula

March 2024        
By Ankit Panda

In the last decade, as North Korea has made tremendous qualitative progress in its nuclear and missile programs, non-nuclear South Korea has responded by shoring up its own precision strike arsenal.

Beginning in 2021, North Korea explicitly stated an intention to develop tactical nuclear weapons, sharply intensifying the perceived threat in South Korea. Since then, Pyongyang has developed an array of new short-range nuclear delivery systems, rendering its ambitions more credible. North Korean leader Kim Jong Un, meanwhile, has indicated that many of these short-range systems will be deployed with so-called frontline units of the Korean People’s Army. Although Kim remains the sole authority on nuclear weapons use in North Korea, he has indicated further that there may be conditions under which the authority to use nuclear weapons could devolve to military commanders. One such condition, outlined in a September 2022 law, could be the degradation of North Korea’s nuclear command-and-control systems in a conflict or the death of the country’s leader. Either circumstance could prompt an “automatic and immediate” nuclear retaliatory attack.¹

North Korea’s adoption of such a fail-deadly posture for its nuclear forces is largely a response to South Korea and the United States. The advanced capabilities available to that alliance, including an array of long-range, non-nuclear strike options supplemented by U.S. nuclear capabilities, present a threat to the survivability of North Korean nuclear forces. More important, however, is the renewed public emphasis on preemptive disarming attacks and decapitation strikes by the conservative government in Seoul, which was inaugurated in May 2022.

Cumulatively, these developments in recent years have contributed to a sharply heightened risk of nuclear war. The two Koreas are mired in an intense security dilemma, which could cause future crises between them to spiral quickly into a possible, large-scale war. In turn, this likely would precipitate North Korean nuclear use, with devastating consequences.

To cope with North Korea’s advancing capabilities, South Korea has become a pioneer in what might be dubbed a strategy of conventional counterforce, namely relying on its advanced non-nuclear capabilities to hold at risk Pyongyang’s nuclear forces. The two Koreas remain stuck in a fierce asymmetric arms competition marked by an action-reaction cycle.

Since the administration of South Korean President Park Geun-hye, from 2013 to 2017, Seoul has spent considerable resources developing a “three-axis” system, which includes a preemptive strike plan known as the “Kill Chain,” an air defense component known as “Korea Air and Missile Defense,” and a retaliatory decapitation plan known as “Korea Massive Punishment and Retaliation.”² The first and third components of these plans are underwritten by Seoul’s growing array of conventional missile capabilities.

North Korean Missile Modernization

Despite acute resource constraints in North Korea, Kim, like his father and grandfather, has ensured that the country’s military readiness remains high. Since taking the reins of power in late 2011, he has made the development of nuclear weapons and their means of delivery a major priority. Between 2013 and 2017, Kim pursued a major nuclear development campaign that culminated in the testing of two different types of intercontinental ballistic missiles (ICBMs) and a thermonuclear device in 2017.

Following the inaugural flight test of an ICBM known as the Hwasong-15, in November 2017, Kim declared his nuclear deterrent “complete” and pivoted by early 2018 to diplomacy with South Korea and the United States. Although this diplomacy temporarily resulted in a pause in North Korean missile testing activity and quickly kept tensions from boiling over as they might have in 2017, it ultimately proved unsustainable. Kim found himself empty-handed after the North Korean-U.S. summit in Hanoi in 2019 when U.S. President Donald Trump rebuffed his demands for sanctions relief in exchange for concessions on uranium enrichment and plutonium reprocessing at the Yongbyon complex.

Since the collapse of diplomacy in 2019, North Korea has doubled down on its nuclear force development efforts. The hallmarks of its ongoing nuclear modernization program center on tactical nuclear weapons, improved responsiveness, and force dispersal. The two latter components represent Pyongyang’s chosen path to a broadly survivable nuclear deterrent, designed to be robust against South Korea’s conventional counterforce strategy.

The diversity of North Korea’s nuclear forces reached breathtaking levels as of early 2024. Pyongyang has indicated that it is actively pursuing everything from lake-submerged, short-range ballistic missile launchers to fixed silos to an autonomous, underwater, nuclear-armed torpedo to rail-mobile missile launchers to submarine-launched cruise missiles.

Kim likely does not yet possess the requisite weapons-grade fissile material to produce a sufficient number of warheads to enable the deployment of this wide range of delivery systems at scale, but he has articulated a goal of increasing fissile material output in an “exponential” manner in the coming years. Kim’s ambition should be taken seriously if not literally. North Korea likely possesses sufficient fissile material to enable the manufacture of 60 to 80 nuclear warheads today.

Given the apparent entry into operation of a new, suspected, experimental light-water reactor; efforts to continue plutonium reprocessing at the old gas-graphite reactor at Yongbyon; and unconstrained uranium enrichment, North Korea slowly is shoring up its stocks of weapons-grade fissile material. Over time, Kim’s ability to flesh out his tactical nuclear forces will grow, and additional nuclear testing likely lies ahead under the ongoing military modernization campaign.

Instability, Arms Control, and the Risk of War

Circumstances between the two Koreas today manifest a clear-cut example of crisis instability risks. Thomas Schelling once described this as the problem of the “reciprocal fear of surprise attack,” in which even if neither side wants a war, the benefits of shooting first in a crisis are perceived as so great for each that both have strong incentives to do so, fearing that the other might act instead.³

North Korea expects to seek tactical surprise and strategic advantage in a crisis by resorting to an early, large-scale nuclear attack to degrade the ability of South Korea and the United States to prosecute a war. Kim has described the purpose of his nuclear forces as twofold: to “deter” and, should deterrence fail, then to “repel” an attack with nuclear use.⁴

The latter would include nuclear use to destroy ports, airfields hosting fifth-generation stealth fighters, command-and-control nodes, radars, and missile defense systems. South Korea, meanwhile, plans to prevent precisely such an attack by shooting the proverbial archers in North Korea by destroying as much of the mobile missile and strike complex as possible with precise, conventional weapons.

As each side publicly communicates these sets of goals, the other’s belief in the advantages and the necessity of shooting first grows. Failing to shoot first comes to be seen as fatal in a crisis. Neither appears to see any benefit in walking back from this fundamental orientation toward preemptive attack.

Critically, the powerful nature of the incentives to attack under mutual postures of preemption is most likely to manifest in escalation even when neither side has an interest in escalation as such. It is the fear that the adversary may preempt that could drive one to consider escalation rational in the course of what might otherwise have been a limited crisis.

Given the poor state of political relations between the two Koreas and the lack of any interest in diplomacy, conditions are hardly propitious for any formal arms control initiatives in the near term. What little remained in the form of confidence-building measures also has largely disintegrated as tensions flared between Seoul and Pyongyang in recent years.

The Comprehensive Military Agreement, agreed by Kim and South Korean President Moon Jae-in during their summit in Pyongyang in September 2018, has been scrapped completely by North Korea. South Korea too has started to resume proscribed activities, such as flying military helicopters along the Military Demarcation Line separating the two sides.⁵

Although limited in scope, the agreement was built on an important premise, namely that accidental clashes could spark serious crises that could quickly propel the two sides into a general war. The agreement sought to prohibit a range of activities within the immediate vicinity of the demarcation line that could increase perceived threats.

In Seoul’s assessment, North Korean violations of the agreement had been ongoing since late 2019.⁶ With the arrival of the Yoon administration, violations increased in frequency and severity. In December 2022, for instance, North Korea flew multiple drones into South Korean airspace in precisely the sort of action that could be interpreted as a precursor to a major armed attack.⁷

South Korea retaliated in kind, sending drones of its own into North Korean airspace. The UN Command, which oversees the implementation of the 1953 armistice that ended the Korean War, assessed that both Koreas violated the armistice with these actions.⁸

This South Korean propensity for disproportionality has manifested acutely under the Yoon administration, which has come to espouse a philosophy that holds that only resolute shows of force can contribute to deterring North Korea. Beyond the drone incident in December 2022, at least two other incidents are evocative of this tendency. In November 2022, a North Korean missile for the first time transgressed the maritime delimitation between the two Koreas. In response, the South Korean side launched three air-to-ground missiles across that same threshold, upping the ante threefold. In the first few days of January 2024, meanwhile, South Korea responded to North Korea’s firing of 200 artillery rounds near the inter-Korean demarcation line by firing 400 rounds of its own.⁹

Worsening prospects for engagement, North Korea’s newfound strategic partnership with Russia in the aftermath of the latter’s brutal, full-scale invasion of Ukraine is likely to raise Kim’s confidence in unconstrained competition with South Korea. Pyongyang’s decision to reject its decades-long objective of unification with South Korea may be in part a reflection of this.

Political Courage and Military Organizational Change

Although arms control continues to be a useful tool for practically reducing the risk of unwanted war on the Korean peninsula, it will require a willing counterpart. North Korea’s post-2019 political and diplomatic recalibration has resulted in a fundamental lack of interest in reciprocating any external overtures from South Korea or the United States.

Although the conditions for proactive arms control and cooperative risk reduction could again manifest on the Korean peninsula at some point, there is an urgency today that demands attention. Policymakers in South Korea and the United States should recognize that even without North Korean reciprocity, they can take measures to reduce the risk of unwanted war and escalation from a conventional war to a nuclear war that do not necessarily require Pyongyang’s involvement.

Such measures would not require compromising general deterrence of North Korea. Instead, South Korea and the United States should recognize that even as North Korea postures its own forces offensively and irresponsibly, some of their own policies and military plans exacerbate the risk of escalation within a conventional war and the risk of nuclear conflict. Unilateral policy change by South Korea and the United States could reduce these risks and lead to a long-term adjustment in North Korean threat perceptions that could be propitious for an eventual return to negotiated, cooperative measures like the 2018 agreement.

Two such measures are easily identified. First, South Korea’s current emphasis on preemption as a matter of its core national defense strategy for dealing with North Korea contributes to escalation risks. To preserve deterrence while reducing escalation pressures, Seoul could adapt its strategic communications toward Pyongyang to emphasize that it would not seek to attack North Korean nuclear forces massively and preemptively early in a war.

Eliminating this source of use-it-or-lose-it pressures for Kim is likely to reduce significantly the risk of nuclear escalation. South Korean policymakers recognize the nuclear risks that manifest on the Korean peninsula as a result of North Korea’s stated intention to resort to the early use of nuclear weapons in a war to mitigate its conventional military vulnerabilities. Yet, preemption continues to be a preferred strategy in Seoul.

Second, the United States can eliminate a prominent source of use-it-or-lose-it pressures for North Korea. Under the Trump administration, the United States publicized a counterproductive effort to seek “left-of-launch” techniques that could disable North Korean missiles prior to their launch in a conflict.¹⁰ Although the precise nature of such capabilities remains obscure and perhaps exaggerated, North Korea is likely to take this seriously. The Biden administration’s 2022 Missile Defense Review retains a commitment to “comprehensive missile defeat,” which John Plumb, U.S. assistant secretary of defense for space policy, clarified involves a continued reliance on measures to left and right of launch.¹¹ This comprehensive approach includes nonkinetic measures, such as possible offensive cyberattacks on North Korean nuclear command and control.

In addition to precise South Korean missiles seeking to preempt his nuclear forces, Kim would have to concern himself with the possibility that an exquisite, undisclosed U.S. offensive cybercapability could sever him from his nuclear forces. Command and control, the central nervous system of any nuclear force, has been considered a unique vulnerability since the 1950s. Yet, as the United States and the Soviet Union discovered early in the Cold War, threatening to hold an adversary’s ability to use its nuclear weapons at risk creates powerful incentives to escalate in ways that may actually undermine a defender’s interests.

The United States and its allies have an interest in depriving Kim of such incentives. Although it would have been ideal for the Biden administration to include these sorts of assurances on interference with nuclear command and control in its 2022 Nuclear Posture Review or Missile Defense Review, it still would be a useful to convey this intention today. Such a statement need not be specific to North Korea, but could apply to all nuclear-armed adversaries of the United States, inclusive of North Korea.

These various measures can be implemented without compromising deterrence of North Korea. Kim will continue to understand that nuclear use can be met with appropriate punishment by the United States and South Korea and that nuclear use will not automatically confer strategic or tactical benefits disproportionate to the costs North Korea is likely to incur.

To preserve deterrence messaging without needlessly contributing to nuclear risks with threats of nuclear force preemption, leadership decapitation, and possible interference in nuclear command and control, the allies should hew closely to the declaratory policy that they articulated in the Washington Declaration from 2023, which simply notes that North Korean nuclear use would be met with a “swift, overwhelming, and decisive” response.¹² What that may mean in practice is left as an exercise in ambiguity for Kim.

Implementing these changes is worthwhile as a means of nuclear risk reduction on the Korean peninsula that does not depend on a change in current political circumstances. Although cooperative arms control and risk reduction efforts are no doubt desirable, North Korea’s unwillingness to pick up the proverbial phone should not be a deterrent to the allies taking matters into their own hands where possible.

Unfortunately, a change of this sort will require political courage in Washington and Seoul, where national leaders must come to terms with the unsustainability of the status quo and thus chart a new path. This is easier said than done. Under U.S. President Joe Biden, North Korea has never topped the U.S. geopolitical agenda. Insofar as his administration has a strategy for the Korean peninsula, it has been one of deepening U.S.-South Korean cooperation and accelerating trilateral cooperation with South Korea and Japan.

For South Korea, meanwhile, the fundamental disposition toward North Korea under the Yoon administration is one of competition paired with the “audacious initiative,” which seeks to lure the North away from its nuclear weapons with promises of economic benefits. Yoon’s initial North Korea policy efforts appeared to be driven substantially by the experiences of several prominent officials who had served in the Lee Myung-bak administration, from 2008 to 2013. In particular, veterans of the twin crises of 2010, when North Korea sank the South Korean naval ship Cheonan and shelled Yeonpyeong Island, killing scores of South Koreans, reentered government with the determination to convey resolute strength at all costs to Pyongyang. As a result, Seoul is reluctant to consider any measures that could be perceived as undermining the projection of strength, even if they might contribute to a reduced risk of a confrontation with North Korea.

For the United States, South Korea’s disposition toward disproportionate retaliation, paired with its significant autonomous conventional counterforce capabilities, are a source of concern.¹³ The Biden administration has undertaken significant efforts to reconcile several countervailing interests with Seoul. On the one hand, it has undertaken new forms of nuclear reassurance at a time when an increasing number of South Koreans view an independent nuclear deterrent for the country as desirable. On the other hand, it has started to seek better operational coordination with Seoul to ensure that South Korea does not escalate crises with North Korea in ways that could be detrimental to U.S. interests. Both of these elements are addressed in the Washington Declaration, which established a new Nuclear Consultative Group while setting up an effort to “closely connect” the existing alliance Combined Forces Command with South Korea’s planned Strategic Command, which will oversee many of the country’s conventional counterforce capabilities.

Seoul and Washington should quietly, candidly, and privately begin exploring the sorts of risk reduction measures that would advance their own interests. This could entail the adoption of the recommendations above in addition to proposing proactively to North Korea potential future cooperative efforts, up to and including formal arms control.

As much as it will be a bitter pill for the allies to recognize that their long-standing objective of a fully denuclearized Korean peninsula is unlikely to manifest soon, focusing on near-term risk reduction is a core interest. Simply put, lowering the risk of nuclear war is worth the trade-offs that come with deprioritizing denuclearization diplomacy with Pyongyang. Doing so does not require any sort of formal recognition of North Korea’s status as a nuclear-weapon power, but simply accepting the reality that is plainly clear on the Korean peninsula.

Coexistence with a nuclear North Korea can be unbounded, unconstrained, and dangerous as it is today. Alternatively, it can be managed. U.S. and allied interests will be better served by turning toward alternatives.

ENDNOTES

1. “Law on DPRK’s Policy on Nuclear Forces Promulgated,” Korean Central News Agency, September 9, 2022, http://kcna.kp/en/article/q/5f0e629e6d35b7e3154b4226597df4b8.kcmsf.

2. Josh Smith, “Analysis: South Korea Doubles Down on Risky ‘Kill Chain’ Plans to Counter North Korea Nuclear Threat,” Reuters, July 26, 2022.

3. Thomas C. Schelling, “The Reciprocal Fear of Surprise Attack,” RAND Corp., January 1, 1958, https://www.rand.org/pubs/papers/P1342.html.

4. Kelsey Davenport, “North Korea Passes Nuclear Law,” Arms Control Today, October 2022.

5. Chad O’Carroll, “ROK Choppers Spotted Near DMZ After Collapse of Military Deal With North Korea,” NK News, December 6, 2023.

6. Ankit Panda, “South Korea Expresses ‘Regret’ at North Korean Violation of 2018 Military Agreement,” The Diplomat, November 26, 2019, https://thediplomat.com/2019/11/south-korea-expresses-regret-at-north-korean-violation-of-2018-military-agreement/.

7. Choe Sang-Hun, “South Koreans’ Steely Nerves Are Shaken by North Korean Drones,” The New York Times, December 28, 2022.

8. Josh Smith, “Both North and South Korea Violated Armistice With Drone Flights, U.N. Command Says,” Reuters, January 26, 2023.

9. Hyung-Jim Kim, “South Korea Says the North Has Again Fired Artillery Shells Near Their Sea Border,” Associated Press, January 6, 2024.

10. Ankit Panda, “The Right Way to Manage a Nuclear North Korea,” Foreign Affairs, December 6, 2018, https://www.foreignaffairs.com/articles/north-korea/2018-11-19/right-way-manage-nuclear-north-korea.

11. “The 2022 Missile Defense Review - A Conversation With John Plumb,” Center for Strategic & International Studies, November 4, 2022, https://csis-website-prod.s3.amazonaws.com/s3fs-public/2023-01/ts221114_Plumb_Defense_Review.pdf.

12. “Washington Declaration,” The White House, April 26, 2023, https://www.whitehouse.gov/briefing-room/statements-releases/2023/04/26/washington-declaration-2/.

13. Ankit Panda, “Indo-Pacific Missile Arsenals: Avoiding Spirals and Mitigating Escalation Risks,” Carnegie Endowment for International Peace, 2023, pp. 21-25, https://carnegieendowment.org/files/Panda_Indo-Pacific_Missiles_final_1.pdf.