Kishida's Realism Diplomacy: Nuclear Disarmament
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Kishida's Realism Diplomacy: Nuclear Disarmament


APLN Senior Associate Fellow Nobumasa Akiyama describes the current government’s blueprint for Japanese leadership, as Japan seeks to promote nuclear disarmament while facing a complex security environment. The original post can be found on the CSIS website here.


Prime Minister Kishida Fumio, elected from Hiroshima, has identified nuclear disarmament as his “life’s work.” During his time as minister of foreign affairs, he hosted President Barack Obama’s visit to Hiroshima. As president of the G7, he hosted the G7 summit in Hiroshima in May 2023. Kishida has publicly stated that he hoped many political leaders would come to Hiroshima to experience the reality of its atomic bombing. He, together with other G7 leaders (and President Zelensky of Ukraine on another occasion), visited the Peace Memorial Park in Hiroshima and jointly reaffirmed the commitment to a common goal of a world without nuclear weapons. The outcome document was the G7 Leaders’ Hiroshima Vision on Nuclear Disarmament.

Meanwhile, the security environment surrounding Japan has made promoting nuclear disarmament more challenging. China and North Korea continue to rapidly expand their nuclear capabilities, while Russia has suggested that it might use nuclear weapons against Ukraine, underscoring the real threat and risks of nuclear warfare. In Japan, the growing awareness of the nuclear threat has led to doubts about the reliability of U.S. extended nuclear deterrence, and for a time, discussions of “nuclear sharing”—allowing nonnuclear weapons states to partake in planning around nuclear weapons and operating nuclear missions—were raised. In this context, disarmament appears to be marginalized in the security policy debate.

The challenge that Japan now faces in arms control, disarmament, and nonproliferation is precisely how to pursue two seemingly contradictory policy goals: promoting disarmament and addressing the nuclear risks posed by China and North Korea (i.e., strengthening deterrence). Many Japanese support their government’s stated goal of a world without nuclear weapons, even in a challenging security environment, and also support the alliance with the United States, including U.S. extended nuclear deterrence.

These two goals are not contradictory. Instead, strengthening deterrence in the immediate term and arms control over the medium to long term can both help reduce security risks. For that reason, both deterrence and arms control should increase in intensity. Furthermore, Japan should take an integrated approach to deterrence, arms control, nonproliferation, and multilateral disarmament diplomacy. To accomplish this goal, Japan should seek to establish a Japan-U.S. bilateral mechanism for systematically consulting and envisioning such integration, which would include addressing how to manage the strategic nuclear relationship with China. This should involve avoiding a potential stability-instability paradox as well as prohibiting China from taking assertive actions at the regional level under its long nuclear shadow.


Historical Background of Japan’s Disarmament Diplomacy

Japan’s disarmament and nonproliferation policy consists of the “Four Pillars of Nuclear Policy,” three pieces of historical context, and two dilemmas. The “Four Pillars of Nuclear Policy” are the four principles that constitute Japan’s nuclear policy, as expressed by former prime minister Satō Eisaku in a policy speech in January 1968. The first is the “three non-nuclear principles” of not possessing, producing, or allowing the introduction of nuclear weapons. Second is the pursuit of nuclear disarmament, rooted in the experience of the atomic bombings in Hiroshima and Nagasaki. Third, to counter nuclear threats, Japan relies on nuclear deterrence based on the Japan-U.S. security treaty. And fourth, Japan reserves the right to peaceful use of nuclear energy. As a resource-poor state, utilizing nuclear energy has been considered an important tool to mitigate energy security concerns. These four pillars are generally maintained to this day as the framework of Japan’s nuclear policy.

In addition, three pieces of historical context must be considered as factors that determine Japan’s nuclear policy. The first is geopolitical conditions in East Asia and the challenges posed by China and North Korea. The second is Japan’s historical experience as the only country to have suffered atomic bombings, in Hiroshima and Nagasaki, and the anti-nuclear momentum that has grown in Japan since the Daigo Fukuryu Maru (Lucky Dragon No. 5) incident in 1954. Third, energy security is needed for economic growth and sustainability in light of the country’s heavy reliance on imported energy sources.

Because of these factors, Japan is faced with two dilemmas. First, as the only country to have suffered wartime nuclear bombings, the Japanese public is generally aware of its “national manifesto” to promote nuclear disarmament. However, in the severe strategic environment of East Asia, U.S. extended nuclear deterrence is indispensable to guaranteeing security, particularly for Japan. Second, Japan, lacking its own resources, has pursued the nuclear fuel cycle in order to promote nuclear power and mitigate geopolitical concerns over fossil fuel supplies. However, the technologies for enriching uranium and reprocessing spent fuel to extract plutonium carry an inherent risk of nuclear proliferation. Japan’s quest for a full-scale nuclear fuel cycle program has led to differences in nonproliferation approaches and friction with the United States, which since the late 1970s has chosen to strongly restrict the proliferation of nuclear fuel cycle technologies.

Threat Perceptions

North Korea and China’s accelerated advancement in nuclear capabilities has significantly deteriorated Japan’s strategic environment. The mounting nuclear threat has served as a reminder of the criticality of extended nuclear deterrence in the U.S.-Japan alliance.

North Korea has been upgrading its nuclear capabilities. At the strategic level, through the possession of nuclear weapons and long-range ballistic missiles, it tries to secure the survival of the regime and acquire tactical nuclear capabilities. This helps North Korea compensate for the inferiority of its conventional forces compared to the United States and South Korea on the Korean Peninsula. By developing diverse nuclear capabilities, North Korea aims to establish an advantage for all contingencies on the Korean Peninsula. It would be reasonable to view North Korea’s efforts as not only tests to develop new missiles but also training to improve the operational capabilities of those missiles.

China is qualitatively and quantitatively enhancing its nuclear arsenal at all ranges. According to the U.S. Department of Defense’s 2021 estimates, China’s number of nuclear warheads is expected to surge to 1,000 by 2030. China reportedly is constructing hundreds of intercontinental ballistic missile (ICBM) silos in the Xinjiang region. If these ICBMs include the DF-41, DF-5B, or other ICBMs that can carry multiple warheads, the number of warheads will inevitably also increase. Additionally, China is attempting to extend the range of its submarine-launched ballistic missiles. For example, China has deployed the JL-2, with a range of 8,000 km, since 2015, and the new, longer-range JL-3 is under development. In this manner, China is striving to improve the survivability and reliability of its strategic nuclear weapons as a strategic deterrent.

China is also establishing an arsenal of medium- and intermediate-range missiles (MRBMs and IRBMs, respectively) capable of carrying new nuclear warheads at the sub-strategic level. The DF-21 is a solid-fuel MRBM that can carry both conventional and nuclear warheads and has a range of about 2,000 km. The latest nuclear variant, the road-mobile DF-26, a solid-fuel IRBM with a range of 4,000 km, was deployed in 2016. It is considered an anti-ship ballistic missile capable of hitting large ships at sea and is also believed to be able to carry a nuclear warhead. In 2021, China deployed the DF-17, an MRBM equipped with a hypersonic glide vehicle, which theoretically possesses the ability to evade missile defense systems.

Globally, Russia’s recent aggression against Ukraine has raised concerns around the world about the potential for nuclear conflict. In attacking its neighbor with the intention of expanding its territorial ambitions and sphere of influence without regard to international law or norms, Russia has reminded the world of the harsh strategic environment in which Japan finds itself in East Asia.

The growing debate in Japan about “nuclear sharing” has been instigated by heightened awareness of the nuclear threat posed by Russia’s invasion of Ukraine. On February 27, 2022, in response to a question on television about the pros and cons of nuclear sharing, former prime minister Abe Shinzo stated that “although Japan is a signatory of the Treaty of on the Non-Proliferation of Nuclear Weapons and has adopted the Three Non-Nuclear Principles, we should not regard a discussion on how the world’s security is maintained as taboo,” suggesting his support for considering nuclear sharing. According to a survey jointly conducted by the Sankei Shimbun and FNN, a television network company, approximately 20 percent of respondents said that discussions about nuclear sharing should be conducted, and more than 60 percent said that, although nuclear sharing should not take place, it should be discussed. Additionally, the possibility of a Taiwan contingency, which was an important issue in the security community even before Russia’s invasion of Ukraine, is now being recognized as a serious concern among the general population.

This indicates growing concern about regional conflicts under the “long nuclear shadow” cast by China. In other words, the risk that China will use nuclear threats to deter the United States from intervening—enabling China to take more assertive action in the region and thereby destabilizing the region or increasing fears of a change in the status quo by force—is now more broadly recognized.

Retrenchment in Disarmament Policy?

Against this backdrop, the Japanese government released a new National Security Strategy in December 2022. This new National Security Strategy represents a departure from traditional self-constraints in defense policy by raising defense spending to 2 percent of GDP and pursuing the possession of “counterstrike” (i.e., long-range strike) capabilities. Measures to deepen U.S.-Japan security cooperation were also discussed as part of strengthening Japan’s defense strategy, as were measures to improve the effectiveness and credibility of extended nuclear deterrence.

For Japan, the balance of power, including nuclear weapons, has tilted out of its favor, making it imperative to respond to the deteriorating security environment. However, despite the need for rapid capacity building to enhance deterrence, arms control and disarmament appear to have become less central to the prime minister’s own agenda in a challenging security environment, even though Kishida, elected in Hiroshima, has positioned the promotion of both as his life’s work.

Nevertheless, Kishida attended the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) Review Conference in 2022, the first appearance of a Japanese prime minister at an NPT Review Conference, and delivered a speech in which he expressed Japan’s determination to “firmly uphold” the NPT as the “guardian” of the NPT. At the same time, under the title of the Hiroshima Action Plan, he proposed concrete measures as the first step of a realistic roadmap to link the “ideal” of a world without nuclear weapons with the “reality” of a severe security environment. Such measures include sharing the importance of continued nonuse of nuclear weapons while working to reduce nuclear risks; improving transparency; revitalizing discussions on the Comprehensive Nuclear-Test-Ban Treaty and Fissile Material Cut-off Treaty while maintaining a downward trend in the number of nuclear weapons; promoting the peaceful use of nuclear energy while ensuring the nonproliferation of nuclear weapons; and spreading awareness of the reality of Japan’s atomic bombings to the world. As part of the last measure, he announced efforts to encourage leaders to visit Hiroshima, indicating that Japan would contribute $10 million to the United Nations to establish the “Youth Leader Fund for a world without nuclear weapons,” a fund to promote projects to bring young people to Hiroshima.

Prime Minister Kishida also announced the establishment of the International Group of Eminent Persons for a World without Nuclear Weapons (IGEP) as a forum in which participants from both nuclear and nonnuclear weapons states can get together and exchange ideas and thoughts beyond their respective national positions and engage in candid discussions concerning a concrete path toward the realization of a world without nuclear weapons. The group’s mandate is not to make direct policy recommendations to the Japanese government but rather to engage the international community in the process of the 11th NPT Review Conference (to be held in 2026) in order to make progress on nuclear disarmament.

Prime Minister Kishida’s speech at the 2022 NPT Review Conference suggests policy priorities that the Japanese government should address itself as part of its disarmament policy, while the establishment of the IGEP will provide a forum for the international community to bridge disagreements about nuclear disarmament. Since his time as foreign minister, Kishida has stressed the need to bridge the deepening divisions in the international community over nuclear disarmament. How to reconcile nuclear disarmament as a kind of national manifesto with policies to address the growing nuclear threat and reduce its risks is an extremely difficult task that will remain a conundrum not only for the Kishida administration but also for the Japanese government in the years to come.

Key Challenges

According to the Japanese Ministry of Foreign Affairs’ policy document titled Disarmament and Non-Proliferation Diplomacy of Japan, Japan’s disarmament and nonproliferation diplomacy is based on a position of active pacifism; the mission of Japan is to achieve a “world without nuclear weapons” for the sake of international peace and stability by pursuing practical and concrete measures to minimize nuclear risks. It is founded on the need to implement measures to contribute to Japan’s security environment through disarmament, consider the inhumanity of nuclear weapons, and recognize that nuclear disarmament is essential to the realization of human security. It is not easy to reconcile how to guarantee the country’s security in an increasingly severe security environment and at the same time reduce threats and promote nuclear disarmament.

The Widening Gap between the U.S.-Japan Alliance and China as a Challenge to Strengthening Deterrence

When considering Japan’s security strategy toward China, a gap between Japan and China needs to be addressed in terms of each country’s ability to mobilize financial and military resources. Japan’s defense spending was roughly the same size as China’s in 1998, but the gap has widened over the years. In 2022, China’s defense spending was more than six times that of Japan and nearly half that of the United States. Chinese military spending grew by a factor of 10.7 between 1998 and 2022, while U.S. and Japanese defense spending only rose by factors of 2.9 and 1.8, respectively. Although dependent on future economic growth, if the current level is maintained, China will spend 10 times as much as Japan on defense by the 2030s. The implications of this trend for procurement of new weapon systems suggests that the United States and Japan will have difficulty maintaining superiority over China in conventional naval and air forces in the region.

Assuming this power gap, the emphasis will shift from conventional fighting focused on gaining maritime and air superiority through large-scale forces, including fighter aircraft and aircraft carriers, to a denial strategy of asymmetrically hindering the opponent’s operational capabilities. It will be critical in this context to establish asymmetric superiority by strengthening cross-domain operational capabilities, combining submarine-based underwater warfare, and investing in dominance in electronic warfare as well as space and cyber. By doing so, Japan and the United States can avoid giving China a “window of opportunity” to raise its expectations of achieving strategic objectives by force.

The 2022 U.S. National Defense Strategy, published in October, lists deterrence by denial, deterrence by resilience, and deterrence by direct and collective cost imposition as necessary elements to form the contemporary deterrence architecture (or “integrated deterrence”). It suggests the need for a deterrence posture that mobilizes more diverse means, including economic and information-based means, rather than the former deterrence mechanisms centered on deterrence by punishment. Several issues need to be addressed in the development of a deterrence posture that uses multiple layers and diverse means. A first question is how non-strategic deterrence can be integrated with strategic deterrence. Second, when the integration of non-strategic and strategic deterrence is required, a question emerges of how to define the division of roles between the United States and its nonnuclear allies amid the nuclear, nonnuclear, and nontraditional domains. Third, there is the question of whether it is possible to find a formula for a sustainable and agreeable threat-management mechanism (what used to be called strategic stability) among China, the United States, and Japan in this complex relationship between the strategic and nonstrategic levels.

Naturally, China would take steps to reduce the effectiveness of such a strategy. Mutual arms escalation will also increase the risk of accidental conflict. Arms control processes are one means of managing such risks. However, China has not expressed interest in nuclear arms control with the United States at this time. Despite having acquired a certain level of deterrence against the United States, China is actively looking to enhance its nuclear capabilities, which are currently inferior to those of the United States at the strategic level. By establishing (or making the United States recognize) “mutual vulnerability” with the United States at the strategic level, China aims to achieve greater flexibility in its actions at the sub-strategic and regional levels.

Such strategic asymmetries and complexities will make it even more difficult to resolve the U.S.-China security dilemma. In addition, resolution of such a situation must take into account Japan’s security concern regarding the stability-instability paradox. It is in Japan’s vital interest to envision how to manage strategic competition in terms of both an escalation crisis and an arms race. In particular, given the challenge of how Japan and the United States can favorably shape strategic competition with China, which has more government discretion and flexibility in allocating resources, including finances, it is necessary to deepen discussion about the role of arms control and specific measures to be taken.

Revitalizing Multilateral Disarmament Diplomacy: How to Deal with Objections from the Global South to the Western-Led International Order

Multilateral diplomacy, including in the United Nations, is facing increasing skepticism due to strategic confrontations among major powers. China and Russia’s consistent defense of North Korea’s violations of UN Security Council resolutions has seriously undermined the problem-solving function of the organization, weakening multilateral diplomacy in nuclear nonproliferation. However, despite the decline in confidence in international organizations, multilateral diplomacy in disarmament and nonproliferation remains an integral part of Japan’s foreign policy, and further strategizing needs to occur on how to incorporate it into the country’s security strategy to reduce threats and to set more a favorable security environment for Japan.

Japan has been promoting nuclear disarmament through a resolution on nuclear disarmament, which it has submitted annually to the United Nations since 1994. Although the United States voted against the resolution in 2000, Japan has been coordinating with the United States to avoid its opposition in light of its security relationship with the United States as well as its national sentiment toward nuclear disarmament. However, a divide over nuclear disarmament has become more apparent in the international community. The 2022 UN resolution (A/C.1/77/L.61) on disarmament acknowledges the adoption of the Treaty on the Prohibition of Nuclear Weapons (TPNW) while attaching importance to disarmament and nonproliferation education regarding the nonuse of nuclear weapons, transparency, and understanding the reality of the atomic bombings of Japan. Although 147 countries, including the United States, United Kingdom, and France, voted in favor, 6 countries, including China and Russia, voted against, and 27 countries, including India, Pakistan, and Israel, abstained, indicating the growing difficulty of bridging the divided camps.

The issue of nuclear weapons reflects the ultimate disparity between countries and has caused much frustration among countries in the Global South. A growing number of these countries have signed and ratified the TPNW, which officially entered into force in 2021, reflecting a growing sense of frustration over the structural inequalities inherent in the NPT.

The economic sanctions imposed by the West on Russia after its invasion of Ukraine have disrupted the global energy and food supply chain, affecting the availability and prices of these essential commodities. Many developing countries that are heavily reliant on imports for their energy and food needs have been severely impacted. Economic security measures such as sanctions against North Korea, Iran, and Russia, as well as decoupling from China, have caused concern among states in the Global South. They fear that they may become collateral damage in the escalating economic tensions between major global powers.

The inequalities surrounding the possession of nuclear weapons, coupled with antipathy toward the economic and political superiority of the so-called West and the “imposition” of liberal values, tend to be easily called upon as anti-American and anti-Western arguments. This anti-Western sentiment, coupled with food and energy supply crises, to some extent, mitigates criticism against Russia’s violation of international law.

For example, the Vienna Declaration, the final outcome document of the first meeting of the parties to the TPNW, held in June 2022, did not explicitly criticize Russia and only condemned nuclear powers in general, even though the meeting was held at the time of the Russian invasion of Ukraine. This reflects the complex international politics that shape the discourse around nuclear disarmament; nuclear disarmament tends to be lost among larger structural problems related to power disparity in the international order.

For Japan, it is difficult to take a clear position in multilateral disarmament diplomacy between countries that support nuclear abolition and those who consider nuclear deterrence necessary. However, effective multilateral diplomacy should be pursued as part of Japan’s security strategy to prevent countries in the Global South from aligning with autocracies and to maintain the effectiveness of nuclear nonproliferation based on the norms of the international nuclear nonproliferation regime.

Policy Recommendations

The Need for New Thinking: Envisioning a Seamless Approach from Nuclear Deterrence to Nuclear Disarmament

To cope with nuclear threats and pursue the goal of a world without nuclear weapons simultaneously, Japan should aim to strengthen its ability to (1) deal with nuclear and conventional threats, (2) shape strategic competition, and (3) maintain an international order favorable to seeking a world without nuclear weapons. To address the first two objectives without military superiority, and to shape the strategic relationship vis-à-vis China, it is necessary for Japan to closely work with the United States to systematically “integrate” deterrence (i.e., building a comprehensive deterrence posture including nuclear, nonnuclear, and extended deterrence) with arms control, nuclear nonproliferation, and multilateral disarmament diplomacy, as well as to conceive of defense diplomacy and strategy as an integrated whole.

The growing imbalance and asymmetry in U.S.-China forces in the Indo-Pacific could result in destabilization of strategic relations and reduced predictability. To mitigate risks associated with such a trend, an arms control arrangement between the United States and China would be valuable. Traditionally, arms control has been an issue exclusively dominated by nuclear-armed states. Given multi-domain entanglement and difficulties in decoupling the strategic and sub-strategic levels of security dynamics, it would be in Japan’s interest to join discussions and dialogue on arms control, a rulemaking process that shapes strategic competition.

The process of pursuing arms control also includes measures for crisis management to prevent unintended escalation and unwanted conflict, as well as dialogue on an arms control framework in its wider definition. Even if dialogue on an arms control framework does not result in a treaty or another form of an institutionalized agreement, the process of confidence building and promotion of mutual understanding is meaningful in terms of reducing the risk of accidental escalation and conveying each side’s message clearly.

Efforts to frame and regulate the arms race with China, however, will be very difficult, as China itself still sees the need to expand its arsenal. In order to engage China in arms control dialogue, it may be necessary to create an environment that encourages China to seek dialogue.

In order to draw China into such a dialogue, it is essential to strengthen deterrence as an alliance by improving the complementarity of U.S. and Japanese forces, along with other forces, in terms of capabilities and deepen cooperation on innovation and supply chains throughout the regional alliance network, with the United States and Japan playing a central role. If such complementarity establishes more effective deterrence, and China realizes that it cannot achieve superiority over the U.S.-Japan alliance through an arms buildup, and therefore that the cost of achieving its strategic objectives is prohibitively high, it will choose to pursue stability in the strategic relationship with the United States and Japan over a continued arms race (Asia’s version of a “double-track” approach).

Effective Bridge Building for the Alliance toward a Seamless Approach

The division between the disarmament and deterrence camps appears to have been made even clearer by Russia’s invasion of Ukraine. The deterrence camp sees Russia’s invasion of Ukraine as a case in which Russia’s nuclear threats curbed U.S. involvement (or Russia restrained escalation out of fear of retaliation by NATO), while the abolition camp sees it as a case of the limits of nuclear deterrence, where nuclear weapons have failed to prevent conflict. In the Japanese disarmament debate, “bridging” means closing the gap between the disarmament (abolition) and deterrence camps, and it appears that bridging this gap has become even more difficult since the Russian invasion of Ukraine. However, the need for bridging also exists in the gap between the United States and Japan. Further gaps exist within the United States, particularly regarding perceptions on strategic stability and the roles of allies between different policy communities in the fields of nuclear deterrence and arms control, as well as regarding alliance management and regional security.

It should be noted that if the United States and China move to resolve the issue of strategic instability between the two countries alone, the stability-instability paradox may be a growing concern for Japan. Stability in the U.S.-China strategic relationship and reduced nuclear risks are generally beneficial to Japan’s security. However, if stability at the strategic level between the United States and China could bring greater discretion in China’s actions at the regional level and signal that more assertive behavior by China is acceptable, Japan’s insecurity could actually increase. To avoid being frightened by such a future prospect, it is necessary for Japan and the United States to have a common understanding of how to manage nuclear risks and threats not only at the strategic level but also at the sub-strategic level, and to envision a common strategy to manage the U.S.-Japan strategic relationship with China. In particular, if China’s increasing stockpile of nuclear warheads in the future could lead to an increase not only in strategic nuclear capabilities but also in nuclear capabilities at the theater level, it is essential that Japan and the United States avoid the stability-instability paradox and have a common understanding of how to manage integrated deterrence and nuclear arms control with China. It goes without saying that Japan’s own strategy and policy concepts are important for this purpose, but a consultative framework should be established to coordinate and align policies between Japan and the United States.

The joint statement by the leaders of the United States and Japan in May 2022 called on China to reduce nuclear risks, improve transparency, and contribute to arrangements for the advancement of nuclear disarmament. With a view to China’s continued buildup of nuclear capabilities, the statement emphasized the importance of strengthening bilateral extended deterrence talks through the U.S.-Japan 2+2 and Extended Deterrence Dialogue. The two leaders also confirmed their willingness to work together toward a “world without nuclear weapons.” In addition, deterrence, arms control, and disarmament were referenced as policy issues that must be dealt with in the context of the U.S.-Japan alliance. However, these items are only discussed in separate contexts in the joint statement. It would make sense to discuss them as a more systematic and integrated strategy.

Currently, as bilateral mechanisms to discuss such strategic and nuclear issues, there exist 2+2 meetings between Japan and the United States at the political level and the Extended Deterrence Dialogue at the working level. Needless to say, they are important mechanisms for discussing the elements and modality of integrated deterrence, including extended nuclear deterrence, in order to enhance the credibility and effectiveness of deterrence against China, North Korea, and Russia at these consultative bodies. They can also help to build an effective deterrence posture through the sharing of strategies and the division of roles between the two countries in a manner that enhances mutual complementarity.

Japan and the United States should reformulate or reform bilateral consultation mechanisms to allow them to discuss and strategize systematically integrating deterrence with arms control, nuclear nonproliferation, and multilateral disarmament diplomacy. Alternatively, they could establish a mechanism to discuss and coordinate the full range of nuclear policy, from deterrence and arms control to nonproliferation and disarmament.

An integrated mechanism of consultation on deterrence, arms control, and disarmament would encourage policy coordination and foster a common understanding between the United States and Japan of the role of the alliance and the concerns of allies that should be considered in defining and managing the U.S.-China strategic relationship. Moreover, such a mechanism could also facilitate a common understanding on how to manage China’s nuclear risks among different policy communities within the United States, namely the nuclear deterrence community, the arms control and disarmament community, and the alliance management community, and create synergy among policies, contributing to effective management of the strategic relationship.

Scrutinizing the Agenda in Multilateral Diplomacy

Pessimism about disarmament is spreading, including arguments that the NPT is unnecessary. However, Japan should recognize the significance of multilateral efforts such as the NPT and play a role in maintaining it. Rules that are followed by all countries, regardless of their power, have several benefits in terms of reducing military and diplomatic costs. Although their efficacy may be uncertain, such rules play a crucial preventive role in regulating nuclear proliferation and gaining legitimacy for counter-proliferation measures.

Russia’s invasion of Ukraine exposed several fault lines in the international community, and the division over nuclear weapons will become more serious in the future in the context of the Global North–South divide. Japan should regard the NPT Review Conference as an opportunity to engage many countries, including those from the Global South, and should actively encourage cooperation where possible. In particular, from the perspective of curbing future arms races, efforts should be made to foster a common understanding of nuclear accountability through the improvement of transparency in nuclear stockpiling, nuclear doctrine and employment policy, and activities associated with nuclear weapons development.

Another important part of the agenda is a moratorium on the production of fissile materials for nuclear weapons. Preventing the expansion of the stockpile of fissile materials will be effective in curbing the trend of the nuclear arms race, and declaring a moratorium on production will be effective as a confidence-building measure. China strongly opposed it at the NPT Review Conference in 2022, and the moratorium could not be included in the draft of the final document (which was not adopted). In addition, reporting of civilian plutonium stockpiles required by the International Atomic Energy Agency’s Guidelines for the Management of Plutonium (INFCIRC/549) is a confidence-building measure regarding the separation of military and civilian nuclear activities, but China has failed to report under this guideline since 2018.


This paper discusses Japan’s nuclear policy and makes three proposals to further effectuate Japan’s disarmament diplomacy in the context of improving its security and maintaining the international order. Japan needs to systematically integrate deterrence, arms control, nuclear nonproliferation, and multilateral disarmament diplomacy in order to achieve its strategic goals. In order to effectively implement such an integrated approach, and avoid a stability-instability paradox, it is important to bridge the gap among policy communities on deterrence, arms control, and alliance management. Through that mechanism, Japan and the United States can jointly envision how to draw China into arms control dialogue and create an environment that encourages China to seek dialogue for threat and risk reduction. It can lead to a common strategy to manage the U.S.-Japan strategic relationship with China as well as a way to manage nuclear risks and threats at both the strategic and sub-strategic levels.

This report is part of Strategic Japan, a CSIS Japan Chair initiative featuring analysis by Japan’s leading foreign policy scholars on key regional and global challenges and the implications for the U.S.-Japan alliance.

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