同盟分断戦略の研究動向と今後の展望 : 理論研究の検討を中心に

Alliance wedge strategies are defined as attempts to prevent, break up, or weaken a threatening or blocking alliance. The question of how to undermine or deal with hostile alliances has remained a pivotal challenge in both academic and policy practice. This paper offers an overview of recent advances in theoretical research on the alliance wedge strategy. Notable scholars specializing in the field of wedge strategies, including Timothy Crawford and Yasuhiro Izumikawa, have engaged in discourse pertaining to the policy instruments employed by states pursuing a wedge strategy and the causal mechanisms that facilitate the dissolution of alliances. Subsequently, a corpus of theoretical and case studies has been amassed, which seeks to elucidate the dynamics of alliance wedge strategies, building upon the aforementioned work. This paper offers an overview of the issues pertaining to the alliance wedge strategy, together with an account of the evolution of research in this field. I then argue that future research development is best served by theoretical research based on the diversification of wedge instruments and the transformation of alliances.