COMPLETION REPORT
Making and Maintaining Japan’s Non-Nuclear Identity: The Global Nuclear Nonproliferation Regime
and Japan’s Nuclear Policy Choice
Dr. Eunil ChoLecturer
Department of Political Science and Diplomacy
Yonsei University
The main purpose of this project is to review how Japan’s non-nuclear policy has been formulated and maintainedsince the mid-1960s. Japan’s non-nuclear policy gives an intriguing research puzzle to international relations
scholars and policymakers. There are two reasons for this. First, Japan has dedicated significant policy interests tothe international nuclear nonproliferation regime, rendering nuclear nonproliferation one of the core and longstanding goals of its diplomacy. Second, Japan has relied upon the security assurance guaranteed by its ally, theUnited States, renouncing nuclear weapons in exchange of the U.S. security commitments with the extended
deterrence. From these, IR scholars and policy community seek to explain Japan’s non-nuclear stance either byemphasizing the pacifist ideal at the core of Japan’s postwar regime or by looking at the security assurance
provided for in the US-Japan security treaty.
My perspective, however, is to provide a theoretical alternative to explain the process of making and maintaining
Japan’s non-nuclear policy when the global nuclear nonproliferation regime had created in the 1960s and 1970s.
In other words, I attempt to fill the lacuna between the structure-based argument and the idea-driven argument. In
explaining Japan’s non-nuclear stance, neither strategic factors nor normative considerations give distinctive
insights to understand international-domestic interaction in shaping Japan’s nuclear policy choice since the 1960s.
Questioning when and how states make their non-nuclear decisions, I suggest that the role of nonproliferation
treaties and norms must be taken into account in explaining the political and normative basis of Japan’s nonnuclear policy choice as to be represented as non-nuclear identity.
From this project, I provide micro-level historical evidence showing how the nonproliferation rules and norms of
the NPT regime have influenced Japan’s nuclear decision from the 1960s. Through detailed process tracing, I lookto the past, seeking out the relevance of the policymaking process from the 1960s and 1970s. This project also
pays attention to the formation and maintenance of non-nuclear identity that leads to shape Japan’s duality to deal
with the nuclear question; on the one hand, the Japanese society pushes its government to support disarmamentmovements; on the other hand, the Japanese government relies on the nuclear deterrence guaranteed by the U.S.
in pursuit of its security in the international relations. The question of how and whether non-nuclear identity has
been formed and changed will give us a valuable insight to understand Japan’s foreign and security behavior in
the field of nuclear nonproliferation and disarmament. Based on this project, I further my research on Japan’scurrent concern regarding the nuclear question after the Fukushima nuclear crisis.

Publication of the Results of Research Project:
Verbal Presentation (Date, Venue, Name of Conference, Title of Presentation, Presenter, etc.)
Date: February 12, 2019
Venue: Japan Foundation Seoul
Conference: Korea-Japan Young Leaders Conference
Presentation: 日本の非核国家アイデンティティーと安全保障政策 (Dr. Eunil Cho)
Thesis (Name of Journal and its Date, Title and Author of Thesis, etc.)
Journal: Diplomacy & Statecraft 32/1(2021)
Title: Impact of the Nuclear Non-Proliferation Regime on Japan’s Non-Nuclear Policy, 1965-1976

Author: Eunil Cho

Book (Publisher and Date of the Book, Title and Author of the Book, etc.)