How do military allies find each other more dependable on security issues, instead of becoming less comfortable relying on each other? How do potential rival states manage to build confidence and shared expectations for a collaborative future, rather than face growing suspicion over each other's strategic intentions? Two sets of allies (U.S.-Japan and U.S.-South Korea) and two sets of potential rivals (U.S.-China and China-Japan) exhibited very different trends in strategic trust in post-Cold War East Asia. These trends defy existing explanations based on power balance, economic interdependence and regime type. This dissertation develops a theory that uses perceptions of national identity to explain variation in trust between governments on matters of national security. The greater difference foreign policymakers perceive between their countries' national identities, the less strategic trust their two governments are expected to share. On the other hand, the less perceived identity difference, the more nation-states are predicted to demonstrate the mutual trust that facilitates security cooperation.
The dissertation shows how perceived identity difference accounts for change in strategic trust by applying the theory to newly collected data from government documents, primary and secondary materials in Japanese, Chinese, Korean and English, and author interviews with high-level policymakers and analysts from all four countries. The project provides in-depth examination of how policymakers look inside each other's countries in an effort to divine geopolitical intentions. The causal story about cycles of perceived identity difference, strategic trust and security cooperation focuses on the nationalist devaluation of other countries that effectively drives spirals in trust and a less stable international environment. Furthermore, nation-states with decreasing trust often coordinate less than overlapping interests and efficient application of resources would suggest. Hence, identity perceptions help explain the absence of cooperation one might expect to see. By developing and applying the theory of perceived identity difference and strategic trust, the dissertation shows how the interaction of competing nationalisms shaped East Asia's security relations after the Cold War.