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YL Blog #58 – China’s Negative Security Assurance and U.S. Extended Deterrence: Concerns and Implications for Japan

Written By

  • Chloe Clougher An Air Force intelligence officer for U.S. Special Operations Command


In December 2023, the Center for Global Security Research (CGSR) at Lawrence Livermore National Laboratory hosted stakeholders in nuclear policy for a two-day workshop on long-term competition and deterrence.[1] The conference focused on a number of key questions, including the competitive nuclear strategy of the People’s Republic of China, how the Biden administration is framing strategic competition in the Indo-Pacific, and U.S. ally perspectives on extended deterrence and allied assurance. Throughout the discussions, there was a common thread: the opacity and rapid changes to China’s nuclear modernization program, and challenges to strategic stability. Below, I highlight my reflections on China’s nuclear modernization and implications of U.S. extended deterrence, drawing from what I learned at the CGSR workshop.

The People’s Republic of China is the sole Nuclear Weapon State (NWS) that ostensibly professes a negative security assurance to not utilize nuclear weapons against any non-NWS, in addition to maintaining a no first use policy.[2] However, China’s recent nuclear modernization explosion, concurrent with renewed statements concerning the inevitability of Taiwan reunification, has created a cloud of doubt among U.S. and allied strategists about China’s nuclear intentions overall. It is probable that Beijing is seeking parity with the U.S. and Russia, and is speeding up production to amass approximately 1,500 warheads by the 2030s.[3] Previously, quantitative nuclear parity and a robust approach to the nuclear balance had not appeared in China’s playbook—yet as hawkish voices take center stage in the Chinese Communist Party, experienced leaders in the People’s Liberation Army Strategic Rocket Force are summarily removed, and decoupling occurs between academic experts and military leadership, China is set on a course to becoming a second nuclear peer to the U.S. with no clear strategy.[4] The PRC’s nuclear modernization program has alarmed close U.S. allies in the Indo-Pacific. Japan in particular has expressed concern on two fronts: U.S. extended deterrence and allied assurance, and China’s negative assurance umbrella.[5]

U.S. extended deterrence for Japan means that the Biden administration must credibly demonstrate both will and capability for reprisal on Tokyo’s behalf in the event of a nuclear or similarly existential attack by the PRC. The U.S. extended deterrence commitment to Japan has two pillars: persuade the PRC that nuclear escalation against Japan will not result in desired outcomes for the Communist Party of China, or that conducting nuclear strikes impacting the island nation will compel intolerable retaliatory measures. For these commitments to influence Beijing’s decision calculus, the U.S. must have an effective nuclear triad with global reach, and have fully assured regional actors that it will safeguard its allies. The U.S.’ 2022 Indo-Pacific Strategy of the United States calls for “integrated deterrence,” to amplify the efficacy of regional deterrence by enabling the U.S. to power project by, with, and through partners and allies[6]. While this strategy and high-level cooperation between the U.S. and Japan is stronger than ever in 2024, two complications potentially hamstring continued credible U.S. extended deterrence for Japan: weaknesses in the air leg of the nuclear triad in the Indo-Pacific, and doubts about the willingness of the U.S. to extend deterrence due to the high stakes of nuclear conflict.

The first issue centers around U.S. limitations to forward presence in theater; due to the geopolitical dynamics of the Indo-Pacific, there is no overarching, interoperable logistics and defense support structure enabling rapid deployment from around the theater to respond in a timely manner to threats from the PRC. In particular, the so-called “tyranny of distance” inherent in the region means that forward nuclear bomber deployment is difficult and slow, and consequently, nuclear options supporting allied assurance are limited.[7] The primary issue in allied assurance for Japan, however, is whether or not regional actors perceive the U.S. has the will to follow through on nuclear defense commitments. U.S. retaliation against a nuclear near peer has far-reaching consequences for the U.S. homeland; White House tolerance for putting American lives at risk on behalf of an allied nation in an entirely different region of the world has also diverged between administrations. The need for the United States to establish allied assurance as a bipartisan guarantee is more vital than ever due to the current nebulous nature of China’s aims with its nuclear program; the PRC may be willing to utilize limited nuclear capability to achieve desired ends regionally, believing that US capability and willingness to extend deterrence to their allies is low.

In January 2022, Japanese Prime Minister Fumio Kishida and U.S. President Joe Biden issued joint statements on the Treaty on the Non-Proliferation of Nuclear Weapons calling for Beijing to avoid escalation, increase transparency, and advocate nuclear disarmament. President Biden restated the U.S. commitment to the defense of Japan, including the Senkaku Islands, under Article V of the Treaty of Mutual Cooperation and Security, using “its full range of capabilities, including nuclear.”[8] Again, in May, the two leaders put forth statements focused on China’s growing nuclear capabilities. In early December 2023, Japan hosted a U.S. delegation at an Extended Deterrence Dialogue, during which the two sides discussed mitigating nuclear escalation, the complexity of the evolving security dynamic in East Asia under the nuclear threats of both the Democratic People’s Republic of Korea and the PRC, and how to mutually enhance allied force posture supporting deterrence.[9]

The impetus for these types of bilateral events is the growing realization from the Japanese that despite the PRC’s negative assurance policy for non-nuclear states such as Japan, a crisis in the Taiwan Strait between the United States and China will occur under a nuclear shadow that may inadvertently hold U.S. regional allies at risk. Further, this nuclear-defined tension is rising concurrent with declining confidence-building measures between the U.S. and China that could otherwise ensure crisis management, and prevent escalation that might inadvertently ensnare or impact close U.S. allies in the region. An additional factor casting doubt over China’s negative assurance for Japan is the closeness of the alliance between Tokyo and Washington—principally because Japan plays hosts to a high number of strategic Pacific U.S. bases and assets, and is anticipated to provide U.S. access, basing, and overflight in the event of contingencies or conflicts in the region. Japanese territory and defense capabilities could thus be viewed by Chinese officials as a proxy for or extension of U.S. capabilities, and draw intentional targeting directed by the Central Military Commission. Collectively, these realizations have driven dramatic changes for Japan, including a doubled defense budget, requests for counter-strike munitions, and strengthening collective force posture with the United States. However, Japan is pivoting from solely relying on the guardianship of the United States, and is seeking out deeper alliances and newfound security ties with Australia and within the Group of Seven.[10] While allies like Japan diversifying their partnerships contributes to integrated deterrence in the Indo-Pacific, security broadening speaks to larger concerns about U.S. allied assurance and reliability in the new world of three nuclear peers.

Disclaimer: All opinions in this article are solely those of the author and do not represent the United States Air Force, the United States Department of Defense, or any organization.

Chloe Clougher is an Air Force intelligence officer who works as a China and Japan subject matter expert for U.S. Special Operations Command.

Photo: B-2 Spirit at Whiteman Air Force Base, Mo. Source: U.S. Department of Defense

[1] Lawrence Livermore National Laboratory. (n.d.). Workshops at Center for Global Security Research. Workshops.

[2] Negative Security Assurances (NSAs). The Nuclear Threat Initiative.

[3] Department of State International Security Advisory Board. (n.d.). Report on deterrence in a world of nuclear multipolarity.

[4] Cunningham, F. S. (n.d.). The Unknowns About China’s Nuclear Modernization Program. The Unknowns About China’s Nuclear Modernization Program | Arms Control Association.

[5] Akiyama, N. (n.d.). How should Japan consolidate the credibility of extended deterrence? The Japan Institute of International Affairs.

[6] The White House. (n.d.). 2022 Indo-Pacific Strategy. U.S. Indo-Pacific Strategy.

[7] Hoffman, S. (n.d.-a). The Assurance Imperative: Forward Presence in the Indo-Pacific. Air University (AU).

[8] The United States Government. (2023, January 13). Joint statement of the United States and Japan. The White House.

[9] Tajima, H. (2023, June 29). Japan, U.S. hold “extended deterrence dialogue.” The Japan News by The Yomiuri Shimbun.

[10] Grady, J. (2022, November 10). U.S. Pacific allies want to work together to Blunt Chinese nuclear threat. USNI News.