Japan's Nuclear Future: Policy Debate, Prospects, and U.S. Interests; Congressional rept

摘要

Japan, traditionally one of the most prominent advocates of the international non-proliferation regime, has consistently pledged to forswear nuclear weapons. Nevertheless, evolving circumstances in Northeast Asia, particularly North Korea's nuclear test in October 2006 and China's ongoing military modernization drive, have raised new questions about Japan's vulnerability to potential adversaries and, therefore, the appeal of developing an independent nuclear deterrent. The previous taboo within the Japanese political community of discussing a nuclear weapons capability appears to have been broken, as several officials and opinion leaders have urged an open debate on the topic. Despite these factors, a strong consensus -- both in Japan and among Japan watchers -- remains that Japan will not pursue the nuclear option in the short-to-medium term. This paper examines the prospects for Japan pursuing a nuclear weapons capability by assessing the existing technical infrastructure of its extensive civilian nuclear energy program. It explores the range of challenges that Japan would have to overcome to transform its current program into a military program. Presently, Japan appears to lack several of the prerequisites for a full-scale nuclear weapons deterrent: expertise on bomb design, reliable delivery vehicles, an intelligence program to protect and conceal assets, and sites for nuclear testing. In addition, a range of legal and political restraints on Japan's development of nuclear weapons. Any reconsideration and/or shift of Japan's policy of nuclear abstention would have significant implications for U.S. policy in East Asia. In this report, an examination of the factors driving Japan's decision-making -- most prominently, the strength of the U.S. security guarantee -- analyzes how the nuclear debate in Japan affects U.S. security interests in the region.