Unsettling Allies, Emboldening Pyongyang
Ambiguity over U.S. nuclear declaratory policy could weaken deterrence on the Korean Peninsula.
Its silence on a key deterrence pledge risks emboldening Pyongyang and unsettling U.S. allies in Asia.
The Trump administration’s National Security Strategy, released in December, has drawn substantial commentary and criticism. Yet, on one of the most consequential issues—U.S. nuclear deterrence—the document is notably thin, offering little beyond a general endorsement of U.S. nuclear modernization. The Defense Department’s National Defense Strategy released last week, added little additional clarity. A year into the second Trump administration, overshadowed by a frenetic series of national security developments involving Venezuela, Greenland and Iran, fundamental questions remain about U.S. nuclear policy, particularly its declaratory policy toward North Korea.
Analysts are left to scrutinize the limited public record for insight into the administration’s approach to nuclear deterrence. One area where that record raises concern is U.S. policy toward North Korea. Subtle but potentially consequential omissions in recent official statements suggest the possibility of a shift away from a decade-long deterrence policy that has underpinned stability on the Korean Peninsula.
The first Trump administration articulated a clear policy in 2018: any use of nuclear weapons by the Kim regime would result in the end of that regime. The Biden administration adopted this position without change, stating in its 2022 Nuclear Posture Review that “any nuclear attack by North Korea against the United States or its Allies and partners is unacceptable and will result in the end of that regime.” President Biden reiterated this policy in April 2023, and Biden administration officials reaffirmed it in bilateral statements with the Republic of Korea (ROK) at the Secretary of Defense level in 2023 and 2024, and at Assistant Secretary of Defense levels in July and December 2023, and January 2025.
To date, the second Trump administration has not restated this commitment. Under Secretary of Defense for Policy, Elbridge Colby, made no mention of this regime ending policy during his visit to South Korea this week. [PA3] And joint statements issued following key bilateral consultations in November and December 2025 made no reference to it either. Such bilateral documents are carefully negotiated, and the absence of this language represents a marked departure from recent practice.
In simple terms, declaratory policy consists of a government’s public statements about when, why, and under what circumstances it would or would not employ nuclear weapons. Such broad statements typically retain an intentional measure of ambiguity balanced by sufficient clarity to shape adversary decision-making, guide military planning, and reassure allies that depend for their security on U.S. nuclear protection. The addition of the North Korea declaratory policy by the Trump administration in 2016 was a significant innovation, making clear to the Kim regime the dire consequences of any nuclear use. An omission or modification of this heretofore unambiguous pledge could have profound implications for the Korean peninsula and the region.
First, would such a change signify that Washington no longer believes that the threat of ending the Kim regime is credible? The U.S. defense establishment is increasingly focused on the Western Hemisphere and the pacing challenge posed by China, while the defense industrial base—by President Trump’s own assessment—has “withered down to nothing.” Meanwhile, North Korea continues to expand both the size and sophistication of its nuclear arsenal, including its ability to strike the U.S. homeland. While the United States and ROK together have the military capacity to end the Kim regime, such an objective in the eyes of Washington may no longer be a viable policy outcome given North Korea’s increasing capacity to threaten the U.S. homeland.
Second, Washington formulated this policy to remove doubt from Kim Jong Un’s calculus about the risk of nuclear use. If that clarity disappears, North Korea may conclude that limited or demonstrative nuclear use—on or near the Korean peninsula—could be survivable. This would likely lower North Korea’s nuclear threshold and also increase the risk of escalation through miscalculation. If Washington changes its approach, it may also face greater pressure in crisis or conflict to negotiate under nuclear duress, constraining U.S. freedom of action and making North Korean nuclear use a newly viable tool of statecraft rather than an act of suicide.
Third, any such policy change would be deeply unsettling to the ROK. It could weaken confidence in U.S. extended nuclear deterrence, the cornerstone of South Korean security. Seoul would be forced to confront the possibility that Washington might tolerate limited regional nuclear use to avoid the possibility of North Korean strikes on the United States. Tokyo would have similar concerns. In a crisis, these allies would face an acute strategic dilemma if the Kim regime concluded it could use nuclear weapons and survive as a government. Such a risk would intensify fears of a decoupling of Washington from Seoul and further fuel domestic pressure in South Korea – and Japan – to pursue an independent nuclear deterrent. That path would be fraught with danger as it could accelerate proliferation pressures in the region and potentially provoke North Korea to preemptively attack before Seoul or Tokyo could field a credible deterrent—producing precisely the war U.S. extended deterrence has long effectively prevented.
At present, it is impossible to draw firm conclusions about the administration’s intent. Public statements on U.S. nuclear deterrence policy have been sparse, and administration officials may yet clarify U.S. policy. Until then, uncertainty will persist about the direction of U.S. nuclear policy toward North Korea.
What is clear is that abandoning—or even blurring—the regime-ending consequences of North Korean nuclear use would represent a sharp break from recent history. It would risk emboldening Pyongyang, unsettling allies, and destabilizing the region. South Korea and Japan can and should shoulder a greater share of the defense burden in the region, but no amount of conventional investment can substitute for resolute U.S. security assurances – to include the assurance that the Kim regime will not survive if it employs nuclear weapons. If Washington walks back this assurance it could render ongoing allied burden-sharing efforts moot, pushing Seoul or Tokyo toward unilateral action, igniting the very proliferation that U.S. policy has long sought to prevent.
Paul Amato is the former Director for Nuclear Deterrence Policy in the Office of Secretary of Defense for Policy. He is a retired Marine infantry officer with twenty-eight years of active and reserve service. Before his government service, he was a practicing lawyer in the private sector.