Speaking last month, South Korea’s new military chief offered a warning to North Korea. Touting the efficacy and precision of his country’s missile capabilities, General Kim Seung-kyum said that South Korea was capable of “sending a fatal blow to the enemy.” Meanwhile, the new South Korean administration under President Yoon Suk-yeol has reinvigorated military planning for preemptive and retaliatory strikes against the North Korean leadership under the so-called Kill Chain and Korean Massive Punishment and Retaliation (KMPR) strategies, respectively.

Ankit Panda
Ankit Panda is the Stanton Senior Fellow in the Nuclear Policy Program at the Carnegie Endowment for International Peace.
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Under the latter concept, South Korea would use conventional missiles to target, among other things, North Korea’s leadership—including Kim Jong Un. These strategies were conceived during a time when North Korea’s nuclear capabilities were relatively more modest and the logic of deterrence by punishment more compelling. However, as North Korea continues to expand its nuclear and missile capabilities, the escalation risks of the KMPR strategy and its overt threats to Kim’s life now significantly outweigh the benefits.

The KMPR strategy was first disclosed to South Korean lawmakers during the Park Geun-hye administration after North Korea’s fifth nuclear test in September 2016. Though the specifics of the plan remain classified and have evolved over the years, the basic contours of what the plan sought to accomplish were described to South Korean media by anonymous military sources, who were likely speaking with authorization, in sufficient detail to outline its strategic purpose:

Every Pyongyang district, particularly where the North Korean leadership is possibly hidden, will be completely destroyed by ballistic missiles and high-explosive shells as soon as the North shows any signs of using a nuclear weapon. In other words, the North’s capital city will be reduced to ashes and removed from the map.

Another source at the time noted the creation of a special military unit dedicated to targeting and killing North Korea’s leadership had been stood up. The strategy is also credible insofar as strike capabilities are concerned: South Korea has no shortage of precision missiles. The Moon administration, seeking to downplay South Korea’s defense capabilities as it pursued diplomacy with Kim, rebranded the strategy as Overwhelming Response (a decision that has since been reversed under Yoon). This basic military strategy is often described as “decapitation,” as it seeks to deter or terminate conflict by removing the head of the adversary’s national leadership.

KMPR is premised on deterrence-by-punishment of Kim. Seoul sought to communicate to the North Korean leader that he could not hope to use his nuclear weapons and live to see another day. This idea has also underpinned U.S. declaratory policy toward North Korea. The Trump administration’s 2018 Nuclear Posture Review notes that “there is no scenario in which the Kim regime could employ nuclear weapons and survive,” and the unreleased but complete Biden administration version may repeat this formulation.

The appeal of this logic of punishment is understandable. As a personalistic dictatorship whose nuclear forces and military are under the control of one person, North Korea may be undeterred from nuclear escalation in the course of a limited conflict by threats of damage against military or economically valuable targets. Accordingly, it must be deterred by threatening to punish its leadership directly. And because North Korea could use its nuclear weapons first to deter and repel a conventional war effort by Seoul and Washington, quickly—and possibly preemptively—killing Kim could avert a nuclear war and limit damage to South Korea.

Unfortunately, this logic runs up against significant qualitative and quantitative changes in North Korean nuclear capability. Continued signaling around decapitation intentions invites North Korea to take especially dangerous steps as it modernizes its nuclear forces and posture. And by continuing to adhere to this approach, South Korea could further increase the risks of rapid and uncontrolled escalation by North Korea in the course of a conflict, defeating the very intent behind this plan.

First, North Korea’s nuclear forces have experienced substantial qualitative refinement and quantitative growth since KMPR was conceived. Between 2017 and 2020, North Korea crossed significant qualitative milestones and began mass production of missile launchers and nuclear warheads. Last year, Kim announced a wide-ranging military and nuclear modernization plan that includes the development and deployment of tactical nuclear weapons. Together, these developments have given North Korea a more responsive and survivable nuclear force—and one capable of inflicting significant damage against South Korea and the United States.

KMPR is meant to be a response to North Korean nuclear use, but North Korea’s expansive nuclear capabilities—and particularly its own development of relatively precise missiles—offer it options that weren’t available at the time the South Korean strategy was conceived. Pyongyang’s plans for nuclear first use can credibly expand to a cover a wider range of South Korean targets as its nuclear force continues to grow. These could include South Korean missile launch facilities, command and control nodes, and other support infrastructure. Seoul can cope by expanding and dispersing its missile forces, and posturing more of them for rapid-response, but the deterrence benefits of these approaches may only be temporary as North Korea expands its arsenal to keep up—the vicious cycle of arms racing.  

Second, in a major crisis or a time of all-out war, it is far from assured that South Korean military forces will have sufficient intelligence, surveillance, and reconnaissance (ISR) capabilities to reliably track Kim’s position and target him with high confidence. A failed decapitation attempt in the course of a conflict—for instance, on one of Kim’s many homes around North Korea—could raise the stakes of what might otherwise have been a conflict with limited aims for Kim and prompt him to opt for significant nuclear use to seek coercive leverage. (Failures to target leadership on faulty intelligence aren’t merely a theoretical concern: the United States tried and failed to kill Saddam Hussein in the early days of the 2003 Iraq invasion.)

Third, given South Korea’s publicly signaled intentions to kill Kim, North Korea’s leadership could be primed to misinterpret wartime strikes by South Korea that do not have the intention of killing the leadership. For instance, various North Korean underground facilities are likely to be targeted by South Korea with precision ballistic and cruise missiles in the course of any major conflict on the Korean Peninsula. If Kim’s position is unknown at the time of the conflict’s start and a facility near his actual location is struck without the intention of actually killing him, Kim could see sufficient cause to escalate to nuclear use to degrade South Korea’s warfighting capabilities.

Even if KMPR has mostly—but not always—been communicated as a retaliatory strategy, Kim may fear preemptive decapitation prior to his use of nuclear weapons. Last month, he used the occasion of the sixth-ninth anniversary of the Korean War armistice to convey that Seoul was “grossly mistaken” if it thought it could preemptively destroy Pyongyang’s ability to use nuclear weapons. Mentioning South Korea’s new president by name for the first time, Kim noted that the “Yoon Suk Yeol regime and its army will be annihilated” if it attempts preemption.

Fourth, the introduction of tactical nuclear weapons may indicate that Kim intends to address his KMPR problem with a somewhat traditional solution. During the 1950s and early 1960s, the United States, starting with the Eisenhower administration, delegated the authority to release nuclear weapons to military units deployed in the field. The basic justification for this practice was that the president’s incapacitation or unavailability in the course of a crisis or war would not preclude the use of nuclear weapons. U.S. leaders believed that delegating authority in this way strengthened deterrence of Soviet threats to Europe.

Kim, like the U.S. president today, retains the sole authority in North Korea to release nuclear weapons. North Korea communicated this to the world when its legislature self-codified the country’s status as a nuclear weapons state. However, at a meeting of the country’s Central Military Commission in June, Kim offered indicators that delegation may be a possibility in the future. In a political system like North Korea’s, delegation of the authority to use nuclear weapons could have negative political implications for Kim’s consolidated political leadership. Nevertheless, it is plausible that Kim may try to strike a balance by only delegating authority in the course of a crisis.  

As North Korea moves toward testing and deploying tactical nuclear weapons, more clarity on this issue is likely to emerge. Continued emphasis on decapitation—and especially preemptive decapitation—by Seoul will give Kim ample incentive to consider delegating nuclear use authority, despite the political risks. Nuclear command and control requires trade-offs, and Kim may opt to maximize what he feels is best for deterrence versus political control. Regardless, South Korea should not hope to solve the problem of deterring North Korean nuclear use by threatening to kill Kim.

Given the many risks associated with continued signaling around leadership targeting and sustaining the KMPR strategy, Seoul should refocus its efforts elsewhere. For instance, the ISR and strike capabilities designed to underpin KMPR can be easily repurposed to support a damage-limiting counter-battery mission against North Korean missile launchers. While targeting mobile launchers will pose challenges commensurate to, if not more difficult than, targeting Kim himself, prompt counter-battery fire may see greater effectiveness.

Above all, the overall shifts in North Korea’s nuclear forces, including its substantial expansion, should prompt a rethink of the utility of deterrence by punishment against North Korea. Threats of punishment can continue to play a role in deterring massive and unlimited nuclear use by North Korea, but Pyongyang’s capability advances since 2016 have opened substantial space for Kim to seek limited nuclear use—including use of tactical nuclear weapons for discrete military objectives. Opting instead for deterrence by denial—conveying to North Korea that even the limited use of nuclear weapons is unlikely to aid in its pursuit of various political aims—may bear more fruit. Seoul has laid the groundwork for denial with its investments in missile defense, but North Korea’s improved nuclear capabilities should prompt a greater emphasis on passive defenses as well, including hardening, concealment, deception, and civil defense.

The U.S.–South Korea alliance, including the Combined Forces Command, should additionally take joint measures to adapt to the new challenges posed by North Korea. Some of this is already underway with the ongoing rewrite of wartime operational plans. With the slated return of joint field training exercises later this summer, the two sides should maintain and enhance readiness to deter and respond to limited attacks by North Korea. These efforts should be paired with joint proposals on possible arms control measures with North Korea that may limit the most acute drivers of instability, such as tactical nuclear weapons, when the conditions for negotiations once again emerge.

Finally, upcoming alliance dialogues on extended deterrence should examine these issues directly. If an overemphasis on punishment-oriented deterrence strategies has revealed gaps in allied or South Korean defense posture, the alliance should respond to mitigate and plug these shortfalls. As the threat posed by North Korea’s nuclear forces shifts, South Korea and the United States will need to adapt in tandem.