核不拡散規範の制度化

――制度形成と変容の要因としての逸脱行為に着目して――

抄録

The nuclear non-proliferation norm, or the limitation on the number of nuclear weapon states, has been institutionalized in the Nuclear Non-proliferation Treaty (NPT) centered regime. It is notable that the 25 years term limitation of the treaty was extended indefinitely and the International Atomic Energy Agency inspection system strengthened in spite of the unfairness of the treaty. Why then, was the non-proliferation norm institutionalized in such a strong regime beyond the merely ideological norm?

Existing research points to the Great Powers preference and/or civil society movements as the factors behind the norm institutionalization. In contrast, this paper focuses on the norm violations and presents a hypothesis that the norm violations prompted the institutionalization of the nuclear non-proliferation norm. Specifically, the norm violations, that is, possession of nuclear weapons, gave policy makers accurate information about the costs and effects of nuclear weapons. Subsequently, many states who renounced nuclear weapon possession created the strong regime in order to bind other potential norm violators.

The theoretical kernel of this argument is the uncertainty of the costs and effects of nuclear weapons. Many policy makers were not well-informed about the effects and costs after the first atomic bomb was introduced. This discouraged policy makers from planning nuclear weapon policies, then dampened their resolve to establish the nuclear non-proliferation regime. Against this background, nuclear non-proliferation norm violations, that is, new nuclear weapon possessors emerged, which reduced the uncertainty around the nuclear weapons and decisively influenced the institutionalization of the nuclear non-proliferation norm.

This paper derived the hypothesis from theoretical consideration. Policy makers faced a range of uncertainties regarding nuclear weapons, including deterrent effect, costs, international relations, and normative behavior of other states. These played a role in their decisions regarding compliance with the norm. The uncertainties of nuclear weapons are reduced and the policy makers clearly recognize the costs and effects of nuclear weapons when the nuclear non-proliferation norm violations occurred. Almost all policy makers renounce possession of nuclear weapons because of their relatively high costs. They then want to bind others to abandon the aspiration for nuclear weapons. Hence it follows that a strict institution is created.

The sections which follow the theoretical consideration empirically verify the above hypothesis. The third section posits that no violations led a weak institution, that is to say the 1968 NPT. The fourth section shows that the policy makers who became informed about the costs and effects of nuclear weapons by norm violations, renounced possession of nuclear weapons and strengthened the nuclear non-proliferation regime to bind other states.