ロシアのウクライナ侵攻で

　旧ソ連は米国の

The nuclear non-proliferation norm is one of the most important norms in international security to date. The Treaty on the Non-Proliferation of Nuclear Weapons was created to implement this norm and took effect in 1970. Since then, the spread of nuclear weapons to non-nuclear weapons states has been curbed to a considerable extent. However, after the end of the Cold War, a couple of countries clearly violated the norm. Sanctions against such misconduct have not been strong enough to enforce compliance. The nuclear non-proliferation norm has been shaken from many angles and severely damaged. Will this lead to the degeneration and disappearance of the nuclear non-proliferation norm and the collapse of nuclear non-proliferation governance?

One of the few existing studies on norm disappearance was conducted by Diana Panke and Ulrich Petersohn. They emphasize the importance of imposing appropriate sanctions on actors who violate an internalized norm. They say that when a lack of appropriate sanctions triggers a cascade of norm violation, the norm will degenerate and disappear or be replaced by another norm. They also argue that a norm will weaken rapidly if it is highly precise, if the environment changes rapidly, and if compliance is not enforced by others. Considering the preciseness of the nuclear non-proliferation norm, the rapidly changing international environment after the end of the Cold War, and the weak sanctions for enforcing compliance when the norm has been violated, will the nuclear non-proliferation norm degenerate?

By examining the results of public polls, behaviors and discourses of states which violated the nuclear non-proliferation norm, and the reactions of other states to the norm violations, this paper demonstrates that the norm is still robust. One reason for its robustness is because there is no alternative norm that can supersede it. In addition, this paper shows that the nuclear non-proliferation norm’s high level of institutionalization as well as the high density of the web of norms related to it have increased the norm’s viscosity. This viscosity is the key to understanding why the nuclear non-proliferation norm has so far not regressed and hence why nuclear non-proliferation governance will not likely collapse in the near future despite all the challenges the norm has faced.

　昨今の原子力平和利用と核不拡散の国際情勢には2つの大きな潮流がある。1つは「原子力ルネサンス」と呼ばれる状況, すなわち米国での原子力回帰, 欧州での脱原子力政策の見直しやアジアの原子力利用拡大等であり, もう1つは北朝鮮の核実験実施, イランの核開発問題, カーン博士の「核の闇市場」, そして核テロの現実化等の核拡散の懸念が一層深刻化していることである。

　原子力平和利用と核不拡散という視点で過去を振り返ってみると, 約50年前の“Atoms for Peace”に始まる原子力平和利用の国際的なスタート, 約30年前のインドの核実験, カーター大統領の核不拡散政策の強化と国際核燃料サイクル評価 (INFCE) 等国際的な秩序形成の動きがあった。そして現在は,

　なお, 本稿は, 日本原子力学会「2006年秋の大会」の講演内容をもとに筆者を加え, 加筆したものである。