When Denuclearization Fades, Japan Holds the Line

“They will never have a nuclear weapon.” With those words, President Trump framed Operation Epic Fury — the US-Israeli strikes launched on February 27, 2026 — an operation to eliminate Iran’s nuclear program. As Prime Minister Sanae Takaichi prepares for her first official visit to Washington and her meeting with President Trump next week, this moment presents a strategic inflection point for Japan. If Washington is willing to use force to prevent Iranian nuclear acquisition, it must also clarify that it will not allow a “North Korea model” — namely, that a state can withdraw from the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), evade inspections, and develop nuclear weapons covertly.

The contrast between Iran’s fate and North Korea’s impunity risks teaching the worst lesson: States that secretly acquire nuclear weapons are shielded from attack, while those remaining in the NPT face military strikes. When the US-Japan summit takes place at the White House, it will be a prime opportunity to reaffirm, at the leaders’ level, their shared commitment to the complete denuclearization of North Korea. The message must be clear: The “North Korea model” cannot be allowed to stand as a successful template for proliferation.

Rising Doubts About the U.S. Nuclear Umbrella

Meanwhile, Japan’s reliance on the U.S. nuclear umbrella faces a deepening crisis of confidence. China’s nuclear expansion, North Korea’s advances, and uncertainty about U.S. priorities are eroding Japanese trust in extended deterrence. In a nationwide survey conducted by the Asahi Shimbun in April 2025, only 15% of Japanese respondents believed the United States “would protect” Japan in a military crisis, while 77% said they did not believe it would. The University of Tokyo ROLES survey (August 2025) found that 39.3% of respondents agreed that Japan is protected by the U.S. nuclear umbrella — a 5.5 percentage-point decline from the same survey one year earlier. In December 2025, an unnamed senior official in the Prime Minister’s Office who advises Takaichi on national security told reporters that Japan “should possess nuclear weapons,” though the official acknowledged this was a personal view. The episode underscored the depth of anxiety within Japan’s security establishment over extended deterrence credibility.

At the Extended Deterrence Dialogue (EDD) held in Washington on February 18–19, 2026, officials from the State Department, the Department of Defense, and their Japanese counterparts confirmed the U.S. commitment to defend Japan “using the full range of capabilities, including nuclear.” Elevating this language to the leader’s level would send a powerful signal — both to the Japanese public and to potential adversaries.

Denuclearization Falls Off the Agenda

Yet even as bureaucrats reaffirmed the “complete denuclearization of North Korea” at the same Extended Deterrence Dialogue (EDD) last month, the political landscape tells a different story. The U.S. National Security Strategy (NSS) released in November 2025 contains no reference to North Korea and no mention of denuclearization — a striking departure from the 2017 NSS, which named North Korea 16 times and called for enforcing denuclearization, and from the 2022 NSS, which pledged sustained diplomacy toward the “complete denuclearization of the Korean Peninsula.” The omission signals — intentionally or not — that Washington no longer treats the resolution of the North Korea problem and denuclearization to be among its highest strategic priorities.

China and Russia have moved further. In November 2025, China released its latest white paper on arms control, disarmament, and nonproliferation. For the first time, the document omitted the phrase “denuclearization of the Korean Peninsula,” a formulation Beijing had consistently included for years. As recently as July 2023, Chinese officials were still publicly reaffirming their commitment to the denuclearization of the Korean Peninsula in diplomatic forums, including at the UN Security Council. This marked the last time Beijing publicly articulated this position.

Russia has been more explicit. In September 2024, Foreign Minister Sergey Lavrov told a Russian news agency: “Applying the term ‘denuclearization’ to DPRK no longer makes any sense. For us, this is off the table.” Moscow’s deepening military and political partnership with Pyongyang accelerated by North Korea’s support for Russia’s war in Ukraine has removed the residual incentive Russia had to press Kim Jong Un toward nuclear rollback.

Now, both major powers with direct influence over North Korea have, in practice, ceased to advocate denuclearization.

Why Continue to Advocate Denuclearization?

Despite these unfavorable trends, continuing to advocate for North Korean denuclearization remains critically important, not as an expression of naïve optimism, but as a strategic necessity.

Accepting North Korea as a de facto nuclear weapons state outside the NPT would hollow out the global nonproliferation architecture. If a state can withdraw from the NPT, build an arsenal, and face no sustained diplomatic consequences, the treaty’s restraining function collapses. Also, denuclearization is not merely a U.S. or Japanese aspiration. It is embedded in multiple UN Security Council resolutions for which Russia and China voted. These resolutions provide legal cover for holding Moscow and Beijing to their commitments.

As long as denuclearization remains the stated international objective, North Korea is framed as the source of the proliferation problem. This matters. If the goal is abandoned, China and Russia gain rhetorical ammunition to argue that U.S. alliances and extended deterrence are the true destabilizing factors in the region — a narrative they are already advancing.

The denuclearization goal is, admittedly, remote. But it is not merely rhetorical. It is the minimum threshold of international consensus built over 30 years of Six-Party Talks, Security Council resolutions, NPT commitments, and joint statements that keep the proliferation problem defined, the pressure framework intact, and the door to future diplomacy ajar.

Policy Recommendations

To counter the spread of the “North Korea model” and keep the goal of complete denuclearization alive, I offer three recommendations.

Reaffirm Denuclearization at the Leaders’ Level

The March 19 Takaichi-Trump summit should explicitly reaffirm the objective of the complete denuclearization of North Korea. This would go beyond the February EDD confirmation and send a political signal. The joint statement should also make clear that the United States and Japan will not treat North Korea as a nuclear weapons state, and that all relevant UN Security Council resolutions remain in full force.

Strengthen Extended Deterrence Communication

The credibility gap revealed in Japanese public opinion surveys demands a more active approach to “assurance” beyond the existing EDD framework. At the March 19 summit, Takaichi should seek from President Trump a direct, personal reaffirmation of the United States’ commitment to the defense of Japan using the full range of U.S. capabilities, including nuclear. Elevating this language to the leaders’ level would send a powerful signal of reassurance — both to the Japanese public and to potential adversaries. Exploring new mechanisms for Japanese participation in nuclear planning consultations, drawing on the “Washington Declaration” model that introduced a formal Nuclear Consultative Group with South Korea, would enhance transparency and understanding of U.S. decision-making on nuclear deterrence. 

Rebuild Regional Nuclear Dialogue

The New START treaty expired on February 5, 2026, leaving the world without any binding constraint on the two largest nuclear arsenals for the first time in over 50 years. President Trump has called for “a new, improved, and modernized Treaty” that includes China. Prime Minister Takaichi has shown support for this approach. Being under the U.S. nuclear umbrella does not preclude Japan from contributing to nuclear arms control. Japan should use its alliance position to shape the post–New START architecture. At the 2025 UN First Committee, China and Russia opposed Japan’s flagship disarmament resolution as a whole (the U.S. abstained), yet voted in favor of individual resolutions on the prevention of an arms race in outer space and disarmament education. These partial convergences offer the most realistic entry points for rebuilding strategic guardrails in an era without binding arms control frameworks. Over time, this could help create a political environment in which substantive discussions on North Korea’s denuclearization can resume.

Conclusion

Denuclearization of North Korea may not be immediately achievable with these policy recommendations. Yet maintaining denuclearization as an explicit objective remains strategically important. It preserves the normative message that nuclear acquisition ultimately leads not to lasting security or prosperity, but to deeper sanctions and isolation. Maintaining this principle helps prevent a model where nuclear weapons guarantee regime survival. Especially in the wake of the strikes on Iran and the leadership decapitation, it has become more important than ever to reaffirm the goal of the complete denuclearization of North Korea.

Mizumi Dutcher is a doctoral candidate at the Johns Hopkins School of Advanced International Studies (SAIS). Her dissertation examines China-North Korea relations under Xi Jinping and Kim Jong Un. She most recently served as a Foreign Policy Fellow in the U.S. House of Representatives, supporting the East Asia and Pacific Subcommittee. Prior to this, she was a journalist at Fuji Television, including serving as Washington Bureau Chief (2018–2022) and an earlier assignment in the Beijing bureau.