Introduction: A Paradigm Shift?
The strategic environment surrounding the Korean Peninsula has fundamentally changed in at least three respects. First, North Korea has moved beyond the earlier denuclearization framework by institutionalizing nuclear weapons as a permanent component of state security. Second, inter-Korean relations have moved beyond the traditional unification paradigm. North Korea now defines relations with South Korea as those between two hostile states, while the concept of reunification has largely disappeared from its official discourse. Third, international consensus on the denuclearization of the Korean Peninsula has weakened as divisions among the major powers have deepened.
These changes raise a fundamental question: if North Korea is unlikely to denuclearize in the foreseeable future, and if the international conditions for achieving denuclearization have also deteriorated, what should be the immediate objective of nuclear policy? This article argues that stopping further nuclear expansion should become the immediate objective, while denuclearization remains the ultimate long-term goal. It also argues that South Korea can play a distinctive role as a “pacemaker” in creating the conditions for such a process.
Post-Denuclearization: From Denuclearization to “Stopping”
North Korea is no longer simply using its nuclear program as a bargaining instrument. It has institutionalized nuclear weapons as a permanent means of national security. In September 2022, the Supreme People’s Assembly adopted the Law on the DPRK’s Policy on Nuclear Forces, which provided for the use of nuclear weapons not only following an actual nuclear attack but also when an attack was judged imminent. In September 2023, North Korea further incorporated its nuclear-force policy into the Constitution, with Kim Jong Un emphasizing that its nuclear-force building policy had become a permanent state policy.
North Korea has since repeatedly reaffirmed that its nuclear status is irreversible. In April 2025, Kim Yo Jong described the DPRK’s nuclear status as a “steadfast choice that can never be reversed” (KCNA, April 9, 2025). In March 2026, Kim Jong Un stated that the DPRK would continue to consolidate its status as a nuclear state and make that status “absolutely irreversible” (KCNA, March 24, 2026). Under these circumstances, it is unrealistic to expect North Korea to denuclearize in the foreseeable future.
This does not mean, however, that the international community should accept the continued expansion of North Korea’s nuclear capabilities. “Stopping” should therefore be distinguished from immediate denuclearization. Stopping means preventing further quantitative and qualitative expansion of North Korea’s nuclear capabilities, including further production of fissile material, expansion of its nuclear warhead stockpile, and qualitative improvement of nuclear delivery systems. These should be treated as a package rather than as separate objectives.
Denuclearization should remain the ultimate goal. But stopping further nuclear expansion should be the more immediate and achievable objective. This distinction does not legitimize North Korea’s nuclear status. Rather, it seeks to prevent the nuclear threat from becoming larger while preserving the long-term objective of denuclearization.
Post-Unification and a Fragmented International Community
The transformation of North Korea’s nuclear policy has occurred alongside a fundamental change in its approach to inter-Korean relations. At the December 2023 plenary meeting of the Workers’ Party of Korea, Kim Jong Un stated that inter-Korean relations had become “relations between two states hostile to each other” and “two belligerent states,” rather than relations between members of the same nation (KCNA, December 31, 2023). In January 2024, the Supreme People’s Assembly declared that reunification with South Korea was impossible under the prevailing conditions and rejected the traditional framework of reconciliation and reunification (KCNA, January 16, 2024).
This shift matters for the nuclear issue. South Korea is no longer primarily regarded as a counterpart in a shared process of national reunification, but increasingly as a foreign and hostile state. North Korea’s nuclear capabilities are therefore also viewed as instruments of deterrence against South Korea and the United States. The post-unification paradigm makes the prospect of denuclearization even more difficult.
At the same time, the international environment has become increasingly fragmented. There was a period when China, Russia, the United States, South Korea, and Japan shared a broad understanding that the denuclearization of the Korean Peninsula was indispensable. China and Russia also supported UN Security Council sanctions against North Korea. That consensus has weakened. Russia opposed the renewal of the UN panel of experts monitoring sanctions implementation, while its strategic cooperation with North Korea has deepened significantly. China has also become increasingly cautious about explicitly emphasizing denuclearization.
Thus, the problem is not only that denuclearization has become less realistic. The international conditions necessary to achieve even a halt to North Korea’s nuclear development have also become more difficult to establish.
Verification and Reciprocal Risk Reduction
Any effort to stop North Korea’s nuclear expansion inevitably raises the problem of verification. Credible verification is indispensable if the international community is to determine whether North Korea is actually complying with constraints on its nuclear program. Yet the experience of the Six-Party Talks demonstrates that verification cannot be separated from the broader security relationship between North Korea and its adversaries.
For Pyongyang, intrusive verification has been closely connected to broader security concerns, while the international community has regarded credible verification as essential because North Korea’s commitments cannot simply be taken on trust. This creates a dilemma: demanding comprehensive verification at the outset may make an agreement politically unacceptable to Pyongyang, while accepting inadequate verification risks allowing continued nuclear development to go undetected.
Verification should therefore be treated as a gradual and reciprocal process, rather than simply as a technical precondition imposed on North Korea. This does not mean weakening the principle of verification. It means recognizing that effective verification is more likely when nuclear constraints and measures to reduce security tensions develop together.
North Korea’s nuclear development should not be understood solely as the product of its internal decisions. It has also developed through interaction with its external security environment. This does not require accepting Pyongyang’s threat perceptions as legitimate. It does, however, require recognizing them as part of the strategic environment shaping North Korean behavior. Stopping nuclear expansion should therefore be accompanied by measures to reduce military tensions and perceived security threats. Nuclear restraint and threat reduction should be treated as reciprocal elements of the same process.
South Korea as a “Pacemaker”
Under these conditions, South Korea should not abandon denuclearization. Rather, it should help create the conditions under which further nuclear development can be stopped. The Lee Jae Myung administration has described South Korea as a “pacemaker” supporting the United States as a “peacemaker” in promoting dialogue with North Korea. This provides a useful starting point, but the role of the pacemaker should be understood more broadly.
South Korea can expand its role from facilitating U.S.–North Korea dialogue to facilitating a broader process of nuclear risk reduction and stopping further nuclear expansion. Seoul has several comparative advantages: experience in direct engagement with North Korea; the ability to coordinate deterrence and diplomacy with Washington through the U.S.–ROK alliance; the capacity to maintain trilateral cooperation with the United States and Japan while sustaining diplomatic channels with China and Russia; and a direct interest in managing military tensions on the Korean Peninsula.
South Korea should therefore combine deterrence, dialogue, and diplomatic bridging. Deterrence is necessary to prevent coercion and escalation. Dialogue is necessary to maintain communication and explore reciprocal constraints. Diplomatic bridging is necessary because stopping North Korea’s nuclear expansion cannot be achieved by South Korea and the United States alone in an increasingly fragmented international environment.
The pacemaker role should consequently be expanded from facilitating dialogue to helping create a reciprocal process linking nuclear restraint, verification, and threat reduction.
Conclusion: Policy Implications
The goal of denuclearizing the Korean Peninsula should not be abandoned. However, the immediate policy priority should shift toward stopping further nuclear expansion and preserving peace and strategic stability on the Korean Peninsula and in Northeast Asia.
Three policy implications follow.
First, the international community should prioritize stopping further nuclear expansion as the immediate objective while maintaining denuclearization as the ultimate goal. This does not represent a change in the ultimate objective, but a change in the strategic priorities for pursuing it.
Second, multilateral coordination should be maintained wherever possible despite geopolitical fragmentation. The weakening of consensus among the major powers makes a comprehensive solution more difficult, but it does not make cooperation irrelevant. The United States, South Korea, and Japan should maintain close coordination while seeking opportunities to engage China and Russia on nuclear risk reduction, crisis management, and regional stability.
Third, South Korea should play a constructive bridging role by combining deterrence with diplomacy. As a pacemaker, Seoul can connect U.S. deterrence with diplomatic engagement, inter-Korean communication with broader multilateral coordination, and nuclear restraint with measures to reduce military tensions.
The nuclear issue on the Korean Peninsula cannot be resolved through unilateral demands on North Korea or through technical management of its nuclear capabilities alone. It requires a reciprocal process in which North Korea’s nuclear restraint is accompanied by credible verification and meaningful efforts to reduce military tensions and perceived security threats. Denuclearization should remain the long-term goal, but achieving even a halt in nuclear expansion requires engagement with the security environment that has shaped North Korea’s nuclear policy. In this process, South Korea can play a distinctive role as a “pacemaker”—not only by facilitating dialogue between Washington and Pyongyang, but also by connecting deterrence, diplomacy, verification, and risk reduction. This is not a call to lower the goal of denuclearization, but to develop a more realistic pathway toward it in a profoundly changed strategic environment.
Sachio Nakato
Professor
College of International Relations, Ritsumeikan University