ポスト冷戦後の核軍備管理

――変質の要因と再活性化の模索――

抄録

The basic structure of nuclear arms control during and after the Cold War was shaped mainly by the structure of the international system and its balance of power. Particularly for the great powers, nuclear arms control was one of the key tools for maintaining the international order they led.

Since the U.S.-Russian New Strategic Arms Reduction Treaty was signed in 2010, nuclear arms control has been at a standstill for a decade. This can be mainly seen as a consequence of power transition in the international system, which has affected the trend of nuclear weapons issues at the unit level as well. The narrowing of the power/nuclear disparity in the post post-Cold War era has brought about dual multipolarity of nuclear arms control among the great powers and between the great and other major countries, suggesting a possibility that the framework as well as regime of nuclear arms control would also be transformed considerably. Especially in multilateral nuclear arms control, difficulties of achieving agreements—through coordination of national and security interests and convergence of objectives among countries involved—increase exponentially.

In addition, the implications for nuclear arms control of the modernization of nuclear forces, and the technological development and proliferation of both nuclear and conventional forces have also being becoming apparent. On the one hand, the development of highly capable conventional forces which could compliment nuclear forces could reduce the role of nuclear weapons. On the other hand, a country facing a threat of its adversary’s advanced conventional weapons would increase its reliance on nuclear weapons in order to offset its inferiority, and thus increase its reluctance to engage in nuclear arms control by which its nuclear activities are bound. Besides that, since conventional weapons do not have equivalent psychological and strategic impact as nuclear weapons, the incentives for promoting conventional arms control are not as high as those for nuclear arms control, which would also impede a progress of nuclear arms control.

The possible transformation of nuclear arms control is complicated due to the dual multiporality of countries involved and diversification of nuclear and conventional forces, making it difficult to predict the future of nuclear arms control. Furthermore, as great power/geopolitical competitions have intensified, countries involved are re-emphasizing the importance of nuclear deterrents in their security policies. However, this is also the moment when nuclear arms control is most needed. It is necessary to renovate framework and discourse on nuclear arms control that takes into account the complexities surrounding nuclear weapons issues.