How Does Diaspora Mobilization Become a Causal Feature of Structural Change?

National integration became a major priority for the Japanese elite’s nation-building policy after World War II. The ambiguous identification of postcolonial Koreans in Japan (the Zainichi Koreans), however, shows that the policy of integration has not developed in a linear or coherent form since those post-war years. This paper examines why long-term migrants—fourth or even fifth generations in some cases—have not fully integrated into host country, and asks how a particular ethnic group becomes engaged in mobilizing across a transnational space until it becomes a diaspora group that is deeply involved in political struggles and international relations. This paper uses the example of the Zainichi diaspora to identify and explore such a transnational space—a space that also provides leverage that can be exploited by individuals or collective actors who make up the elites of both the host state and the homeland. By focusing on the changing roles of the Korean Zainichi diaspora in the light of shifting policies that reflect Japan’s external security environment, the article argues how host state policies allow an entity such as the Zainichi diaspora to transform itself into an agent capable of structural change.