Maintaining Japan’s Non-Nuclear Identity: The Role of U.S. Security Assurances

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Part of the US-Japan Alliance Project

Excerpt from “Maintaining Japan’s Non-Nuclear Identity: The Role of U.S. Security Assurances” by Yuki Tatsumi, Chapter 7 in Security Assurances and Nuclear Nonproliferation, edited by Jeffrey Knopf (Stanford Security Studies, July 2012).

Japan has a unique profile among the non-nuclear weapon states in the world: it voluntarily renounced the possession of nuclear weapons despite having one of the world’s most advanced civil nuclear energy programs and the technological capacity to become a nuclear-armed state. Moreover, Japan’s renunciation of nuclear weapons is also a part of its post-World War II national identity, an identity that still shapes Japan’s self-image today.

Since the 1990s, however, rising tensions on the Korean peninsula over North Korea’s nuclear program have prompted debate within Japan regarding its decades-old non-nuclear policy. While there is little sign that Japan will abandon this policy in the near future, frequently expressed concerns about Japan’s joining the nuclear club make it important to consider what contributed to Japan’s decision to forswear nuclear weapons and the role security assurances have played in bringing about and maintaining this decision. For Japan, the most important assurance has been a U.S. security guarantee in the form of a bilateral alliance and extended nuclear deterrence. Given the considerable impact that the Fukushima Dai-ichi nuclear power plant accident has had on the Japanese public’s attitude toward nuclear power, antinuclear sentiment seems to have regained strength in Japan since the March 2011 earthquake and tsunami triggered widespread damage and radiation releases at the four power stations in Fukushima Dai-ichi. Still, given that Japan continues to face nuclear weapon threats in its neighborhood, the question of whether Japan might go nuclear remains important.

This chapter proceeds in four sections. First, it traces the evolution of Japan’s non-nuclear policy since 1945. Second, it describes the security assurances that have been offered to Japan and the role that those assurances have played in Japan’s decision to renounce nuclear weapons and maintain this decision. In this context, it reviews past debates within Japan on a nuclear option. Third, it discusses how different security assurance hypotheses may be applicable to explain Japan’s behavior. The chapter ends by exploring the key factors likely to shape future debates in Japan on the possession of nuclear weapons, including how perceptions of the reliability of U.S. security assurances may affect those debates.

The chapter concludes that Japan’s non-nuclear weapon status has multiple causes. In addition to the positive security assurance from the United States, Tokyo’s recognition of the negative regional security implications of going nuclear and domestic antinuclear sentiment have also been important. This suggests that a future weakening of the U.S. security guarantee might not automatically lead Japan to reconsider its decision. Yet attention to the credibility of the security assurance still remains a prudent nonproliferation investment.

About the Book

While policy makers and scholars have long devoted considerable attention to strategies like deterrence, which threaten others with unacceptable consequences, such threat-based strategies are not always the best option. In some cases, a state may be better off seeking to give others a greater sense of security, rather than by holding their security at risk. The most prominent use of these security assurances has been in conjunction with efforts to prevent the spread of nuclear weapons.

Ongoing concerns about the nuclear activities of countries like Iran and North Korea, and the possible reactions of other states in their regions, have catapulted this topic into high profile. This book represents the first study to explore the overall utility of assurance strategies, to evaluate their effectiveness as a tool for preventing nuclear proliferation, and to identify conditions under which they are more or less likely to be effective.

The book can be found through the Stanford University Press

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