North Korea’s Dangerous Turn

In January 2021, North Korean leader Kim Jong Un told his country – and the world – about the plans he had for the evolution and modernization of his nuclear deterrent. He outlined a far-reaching, ambitious menu of military modernization goals. Among these were tactical nuclear weapons, a capability that North Korea had until then not formally sought.

The development and eventual deployment of tactical nuclear weapons by North Korea will represent the most serious negative development for peace and security on the Korean Peninsula since the country's development of intercontinental-range ballistic missiles capable of ranging the United States. The implications include a heightened risk of nuclear escalation, greater potential for nuclear accidents and mishaps, and greater strain on the South Korea-U.S. alliance.

Tactical nuclear weapons have no universally accepted definition; indeed, the very idea of any nuclear weapons use representing a “tactical” development is contested, with analysts arguing instead that any nuclear weapon use anywhere would have “strategic” implications. Despite these debates, there are three general principles that have come to be associated with tactical nuclear weapons.

First, these weapons feature a deliberately reduced nuclear explosive yield. While some weapons considered “tactical” would still yield a significant proportion of the energy released by the nuclear weapons used by the United States against the Japanese cities of Hiroshima and Nagasaki in 1945, their yields would be relatively smaller than the significantly more damaging weapons that exist in nuclear arsenals – including that of North Korea’s – today. Until North Korea carries out a seventh nuclear test or otherwise directly reveals information concerning the explosive yields it seeks with its tactical nuclear weapons, its adversaries will be left to speculate on this matter

The second and third features of tactical nuclear weapons are where North Korea has provided some greater clarity. The second feature associated with tactical nuclear weapons is that their deployment occurs on relatively short-range delivery systems. In April 2022, Kim oversaw the test of a short-range missile system that flew for just about 110 kilometers; North Korean state media described that missile as a system intended for the delivery of “tactical nukes.” This was the first time North Korea had directly connected a tactical nuclear weapons delivery role to a tested delivery system, and it turned to be an exceptionally short-range missile. North Korea could well seek to expand the range of missile systems that might play a role in the delivery of tactical nuclear weapons, but so far, Kim has opted not to. Kim has, however, alluded to making tactical nuclear weapons lighter and physically smaller, which could allow North Korea, for the first time, to place nuclear warheads on its growing arsenal of cruise missiles.

The final feature of tactical nuclear weapons, while not ubiquitous through the nuclear age, is the tendency of states that field them to seek to delegate the authority to use these weapons away from high-level political leadership to relatively low-level military commanders. This practice, for instance, describes how Pakistan’s military would operate its Hatf IX or Nasr short-range missile system capable of tactical nuclear weapons delivery. During the early years of the Cold War, the United States similarly delegated authority for the use of nuclear weapons. The propensity of nuclear states to opt for the delegation of authority depends on a range of factors, including their broader nuclear posture and civil-military relations.

In North Korea, a decision on delegating the authority to use nuclear weapons would not be taken lightly. Currently, Kim – and only Kim – is the competent authority to issue orders to use nuclear weapons. By delegating the authority to release weapons, Kim would risk diluting his power to certain parts of the Korean People’s Army. But, concurrently, the logic of deterrence may make delegation appealing. After all, South Korea publicly has indicated since 2016 that it maintains military plans and capabilities to kill Kim (albeit in retaliation for nuclear use). If Kim is concerned that his being the sole authority for the release of nuclear weapons creates strong incentives for his adversaries to seek a decapitation attack on his person, the strategic logic of delegation may be all too appealing.

There are some indications that matters may be heading in this direction in North Korea. In June, Kim oversaw a meeting of the Central Military Commission of the Workers’ Party of Korea. While the state media readout of decisions taken was vague, parts of the meeting indicated that tactical nuclear weapons were likely discussed. State media noted that Kim had made a decision on “adopting important military measures to enhance the operational capabilities of the frontline units,” echoing language that had been used after the April 2022 short-range missile test, indicating that these units may receive the authority to use nuclear weapons.

Kim does not necessarily need to pre-delegate the authority to release these weapons in peacetime; he could choose to delegate only in a crisis, communicating that he had done so publicly to the United States and South Korea as he seeks to enhance deterrence of an attack on himself and his regime.

Despite these shifts in North Korean capabilities, the country’s broader nuclear strategy largely remains unchanged for the moment. Tactical nuclear weapons represent a logical evolution of North Korea's nuclear strategy, which has always been premised on reserving the right to use nuclear weapons first against conventionally superior adversaries. In the Kim Jong Un era, since at least 2013, North Korea has described two primary objectives for its nuclear weapons. The first of these is to deter an invasion of its territory. The second is to “repel” an invasion of its territory should deterrence fail. These objectives are both explicitly stated in the country’s 2013 law codifying its status as a nuclear state. Kim reiterated these objectives in a speech at a military parade in April 2022. However, because North Korea’s tactical nuclear weapons may be perceived by the country’s leadership as more credibly useable, they stand to increase the possibility of nuclear escalation in a crisis.

The operational practicalities of deploying tactical nuclear weapons will also increase nuclear risks in other ways. For instance, North Korea is currently thought to store its nuclear weapons in a centralized manner and only in the northern part of the country, near its long-range strategic missile operating bases. If tactical nuclear weapons are to be deployed near the inter-Korean Military Demarcation Line to the south, Pyongyang will likely seek to build multiple warhead storage facilities. The dispersal of weapons storage and the possibility of regularized in-field handling of nuclear weapons by the Korean People’s Army raises the risks of nuclear accidents and even the possibility of unauthorized nuclear use (for instance, due to authority being delegated). North Korea has yet to definitively move in this direction, but the strategic logic driving its pursuit of tactical nuclear weapons will generate pressures to consider dispersed storage.

For the United States and its ally, South Korea, tactical nuclear weapons will represent a serious challenge. North Korea has long sought to stress the alliance through its development of nuclear weapons. In the last few years, the main challenge for the United States has been to assure South Korea (and Japan) that it would risk its own cities, which are vulnerable to North Korea’s intercontinental missiles, to defend theirs. With tactical nuclear weapons, another challenge presents itself. South Korea and the United States may diverge on how to cope with the problem of tactical nuclear weapons. Seoul may be more likely to emphasize preemption, a core component of its military plans for North Korea, but the United States may otherwise focus on deterrence-by-denial – or communicating to Pyongyang that its use of tactical nuclear weapons would have a negligible effect on the ability of the alliance to continue military operations.

Because North Korea’s pursuit of tactical nuclear weapons is still a novel development, the alliance is in the course of adapting. Upcoming dialogues on extended deterrence between the two countries are likely to closely examine these problems and, on the military side, the alliance’s ongoing effort to rewrite and update war plans will similarly take into account the possibility of tactical nuclear weapons use by North Korea in a range of contingencies.

North Korea’s turn toward tactical nuclear weapons emphasizes how far away the prospect of a denuclearized Korean Peninsula lies today. As Pyongyang proceeds to take its nuclear forces in a more dangerous direction, there’s little apparent evidence that the United States and South Korea are interested in fundamentally reevaluating their policy approach to one that focuses on meaningful nuclear risk reduction and even arms control with Pyongyang. In the short term, the most dangerous consequence of North Korea’s continued possession of these weapons continues to the prospect of a nuclear war. With no meaningful measures of nuclear restraint on the Korean Peninsula, these risks are set to grow boundlessly, with resources serving as the sole limit on North Korea’s ambitions. The urgency of stemming escalation risks with North Korea should drive Seoul and Washington reevaluate and change course.