ABSTRACT Why has Japan shifted towards a more active security posture since the end of the Cold War? Japan’s security policy under Prime Minister Abe has triggered numerous discussions on the changing nature of Japan as a security actor. This article identifies two independent variables—the balance of power calculations and secure access to the maritime commons—that informs Japan’s security policy trajectory. It argues that Japanese strategy is best described as ‘maritime realism’, a posture in which liberal internationalist and realist elements draw upon principles of maritime strategy to fuse together. Japan has not only actively facilitated US commitment to maritime Asia but also focused on expanding its role in maritime security as the maritime space in the Indo-Pacific has increasingly become a contested space. While Tokyo’s security policy corresponds with structural realist predictions, they have also been frequently expressed in liberal internationalist language given the peculiar nature of the role of navies. This article’s findings advance theoretical debates on alliance politics and great power competition by integrating international relations and concepts in strategic studies. It also contains significant explanatory power in assessing the trajectory of Japan’s defence policy since the end of the Cold War.

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解释日本冷战后的安全政策轨迹：海上现实主义

摘要 为什么日本在冷战结束后转向更加积极的安全态势？安倍首相领导下的日本安全政策引发了关于日本作为安全行为者不断变化的性质的众多讨论。本文确定了两个独立变量——权力平衡计算和对海洋公域的安全访问——它们为日本的安全政策轨迹提供了信息。它认为，日本的战略最好被描述为“海洋现实主义”，在这种姿态中，自由国际主义和现实主义元素利用海洋战略的原则融合在一起。日本不仅积极推动美国对亚洲海洋的承诺，而且随着印太地区的海洋空间日益成为一个有争议的空间，还专注于扩大其在海上安全中的作用。虽然东京的安全政策符合结构现实主义的预测，但鉴于海军角色的特殊性质，它们也经常以自由国际主义的语言表达。本文的研究结果通过在战略研究中整合国际关系和概念，推进了关于联盟政治和大国竞争的理论辩论。它还具有评估冷战结束以来日本国防政策轨迹的重要解释力。本文的研究结果通过在战略研究中整合国际关系和概念，推进了关于联盟政治和大国竞争的理论辩论。它还具有评估冷战结束以来日本国防政策轨迹的重要解释力。本文的研究结果通过在战略研究中整合国际关系和概念，推进了关于联盟政治和大国竞争的理论辩论。它还具有评估冷战结束以来日本国防政策轨迹的重要解释力。