Nuclear Deterrence Norms and Normative Learning: The Development of Japanese Nuclear Deterrence Policy

Japan today primarily relies on US Extended Nuclear Deterrence (END) and the threat of nuclear retaliation to deter nuclear threats, which has often led to Japanese policymakers advocating global denuclearization on the world stage on one hand while providing a full-throated defense of the US nuclear arsenal on the other, opening Japanese policymakers to accusations of ‘nuclear hypocrisy’. Such a belief in the necessity of nuclear retaliation to deter nuclear threats has not changed even after the addition of a Japanese Ballistic Missile Defense (BMD) system in 2003 to mitigate the threat of nuclear ballistic missiles. For scholars of nuclear deterrence, such a phenomenon is not uniquely ‘Japanese’ and is widely seen as an accepted ‘fact’ of how nuclear deterrence operates. For such scholars, given the nuclear threats that Japan faces in China and a newly nuclearized North Korea, as well as the multiple restrictions, both domestic and international, that prevent Japan from pursuing a domestic nuclear program, it is thus no surprise that Japanese policymakers continue to defend US nuclear weapons even at great political cost.

This thesis, however, argues that such Japanese perspectives, rather than being factual statements and a natural conclusion of any state operating in the international system, are instead theoretically assumed nuclear deterrence ‘norms’ that have been constructed and institutionalized into policy by Japanese policymakers as a result of a ‘deterrence socialization’ process. By examining two key normative perspectives of nuclear weapons present in Japan’s nuclear deterrence policy, this thesis will demonstrate how such a process of deterrence socialization has seen the US, Japan’s main security ally, ‘teach’ and persuade Japanese policymakers to adopt their perspectives and conceptualization of how nuclear deterrence operates, which in turn leads to Japanese policymakers ‘learning’ and constructing such norms in accordance with Japan’s socio-political context and institutionalizing them as policy.