Last week, Pete Hegseth, the nominee for U.S. defense secretary, made waves in South Korea by alluding to “[North Korea’s] status as a nuclear power” in his written answers to advance policy questions from the U.S. Senate Armed Services Committee. Hours after his inauguration, President Donald Trump himself used that same phrase to describe North Korea in off-the-cuff remarks to reporters.
South Korea’s foreign ministry pushed back on Hegseth’s answer, underscoring the country’s longstanding view that North Korea’s possession of nuclear weapons cannot be legitimated and that “Under the NPT (Nuclear Nonproliferation Treaty), North Korea can never be recognized as a nuclear-armed state.”
Whether or not Hegseth’s answer reflects the new administration’s policy, this remarkable exchange underscores what is likely to be an important source of friction between Washington and Seoul: the United States’ adoption of a fundamentally different approach to managing the risks posed by North Korea’s nuclear program. At its core, it is a debate about the future of the “denuclearization” of the Korean Peninsula.
Seoul’s opposition to legitimating Pyongyang’s nuclear status is understandable: North Korea remains the only non-nuclear weapon state that ever signed the Nuclear Non-Proliferation Treaty (NPT), cheated on it, built nuclear weapons, and got away with it. Just five countries—the United States, the Soviet Union, the United Kingdom, France, and the People’s Republic of China—are afforded the status of a legitimate nuclear weapon state under the treaty, by virtue of having tested nuclear weapons prior to January 1, 1967.
North Korea, having conducted its first nuclear explosive test in 2006, does not satisfy this criterion. Given this, Seoul’s assertion on Pyongyang’s status in the context of the NPT is both literally and legally correct: North Korea will never be a nuclear weapon state under the NPT, regardless of what any official, nominated or confirmed, in the United States may suggest. But driving Seoul’s opposition is the considerable anxiety that the United States may shift to a different objective in its relations with North Korea, after more than three decades of focus on denuclearization.
Denuclearization evokes a deceptive simplicity. In 2025, it serves as coded language that means the disarmament of North Korea. But its introduction into the international diplomatic lexicon in the early 1990s emerged out of a context that bears revisiting.
In 1958, five years after the end of the Korean War, the United States deployed tactical nuclear weapons to South Korean territory. These weapons were intended to offset North Korea’s conventional military superiority over South Korea, and they remained the only nuclear weapons on the Korean Peninsula for several decades.
In December 1991, as a result of the U.S.-Soviet presidential nuclear initiatives and the tectonic geopolitical shifts that accompanied the end of the Cold War, the United States withdrew all of its tactical nuclear weapons deployed overseas to Asia, including those on the Korean Peninsula. One month later, the two Koreas concluded the historic Joint Declaration on the Denuclearization of the Korean Peninsula, which obliged both countries to refrain from developing nuclear weapons and relevant enabling technologies.
Since then, much has changed on the Korean Peninsula. For almost two decades now, North Korea has built, exploded, deployed, and continues to widely manufacture nuclear weapons and their delivery systems, including those that can range the entirety of the continental United States. It also has a nuclear doctrine that allows for preemptive nuclear attacks. These developments have obvious deep implications for both South Korean and U.S. security, yet the official policy goal of seeking denuclearization above all remains.
Now, for the United States, North Korea is no longer appropriately categorized as a nonproliferation problem, but a problem of nuclear deterrence. Put simply, the overarching U.S. interest vis-à-vis North Korea is the prevention of nuclear war. U.S. nuclear weapons and the combined capabilities of the U.S.-South Korea alliance contribute to the deterrence of a deliberate resort to war by Kim.
But, as the United States discovered with the Soviet Union during the Cold War, a reliance on nuclear deterrence alone does not lead to absolute safety. So, with North Korea today, the United States must give greater consideration to the myriad pathways to possible nuclear use that may stem from miscalculation, misperception, or accidents.
The fact of nuclear deterrence between the United States and North Korea may have once been a controversial subject but is less so today. Consider that the unclassified summary of the former president Joe Biden administration’s nuclear weapons employment guidance speaks of the need to deter North Korea alongside Russia and China. This reflects deeper shifts in U.S. thinking: In 2022, U.S. Strategic Command hosted the first-ever nuclear deterrence symposium dedicated to North Korea—a privilege that had solely been afforded to Russia and China.
No doubt for North Korea, a small country of 26 million people with a gross domestic product a fraction of that of the United States, these developments confer some abstract, de facto status: The world’s preeminent nuclear superpower now acknowledges it as its third nuclear-armed adversary because of the obvious risk of nuclear war between them.
As my colleague Toby Dalton and I argued in these pages more than two years ago, the United States and even South Korea have already quietly accepted North Korea’s nuclear status in all the ways that practically matter. And with a new administration in office, Seoul may find that U.S. officials become less constrained by the decades-old rhetorical practices that have long bounded the ways in which North Korea is spoken of in official contexts—as has already happened.
But instead of viewing this as an intolerable risk, South Korea, along with the United States, should reframe their approach to dealing with North Korea to one that centers on the risk of nuclear war over nuclear possession in the near-term.
The singular focus on denuclearization need not be discarded entirely, but neither should it remain front and center. There is already some precedent for this: The 2024 U.S.-South Korea Security Consultative Meeting suggested that “sanctions and pressure” should “dissuade and delay [North Korea’s] nuclear development” and entirely omitted the word “denuclearization.” Colin Kahl, former under-secretary of defense for policy in the Biden administration, acknowledged in 2021 that denuclearization would be a “long-term objective” but noted the existence of other short-term priorities, including the reduction of tensions and the threat posed by North Korea.
But, perhaps most importantly, denuclearization has become something of a straitjacket for more flexible policy and even deterrence thinking toward Pyongyang. By centering the principle of nonproliferation, Washington and Seoul have deprived themselves of opportunities to explore new forms of engagement with Pyongyang that could instead address the most glaring threat to their interests stemming from North Korea’s possession of an increasingly capable and diverse nuclear arsenal: unwanted nuclear war.
Elbridge Colby, Trump’s nominee for under-secretary of defense for policy, argued last year that “arms control” could be one such “attainable” policy goal short of denuclearization. While an arms control approach toward Pyongyang is no longer a novel idea, it is one that has yet to be broached proactively in diplomatic overtures. At the 2022 Carnegie International Nuclear Policy Conference, Bonnie Jenkins, then the under-secretary of state for arms control and international security, suggested “arms control can always be an option,” only to have that walked back less than a day later by the U.S. State Department’s official spokesperson amid concern in South Korea. The Trump administration may well choose to explore this territory.
Seoul should expect a focus on risk reduction to become a more singular focus in Washington—not because of the foreign policy inexperience or unorthodoxy of a second Trump administration, but because U.S. and even allied interests have now long been pointing policy in this direction. A good example of this view now being openly articulated is by Secretary of State Marco Rubio, who called for measures to reduce the risk of “inadvertent war” on the Korean Peninsula.
To be sure, as allies, Washington and Seoul must stay in lockstep about the principles that will guide their approach to dealing with North Korea. Pyongyang remains obstinate on its openness to negotiations, but the next four years will provide an opportunity to revisit North Korea policy. U.S. and South Korean policymakers should be ready to seize this opportunity to rethink North Korea policy to advance the cause of reducing nuclear risks.
