An implacable and formidable foe during the Second World War, Japan is now one of the United States' most reliable and capable allies in the Indo-Pacific. A region in transition, the Indo-Pacific includes four of the world's nine nuclear powers and the world's three largest economies. Amidst a dynamic and devolving threat environment, the region is struggling to accommodate the dominant rise of China and an increasingly capable nuclear-armed North Korea. Against this unstable security backdrop, Prime Minister Shinzo Abe's administration is taking unprecedented post-war actions to ensure Japan's national security and prosperity. This study identified the Abe administration's omnidirectional "Proactive Contribution to Peace" approach to Japan's national security strategy, focusing on its diplomatic, informational, military, and economic policies. Facing a regional security order increasingly dominated by China and punctuated by DPRK missile launches, Japan is entering a realist period marked by an assertive security mindset. Its anti-war national identity, democratic model of economic success, and military support role within the U.S.-Japan alliance have historically characterized Japan's security outlook. However, Japan's controversial reinterpretation of Article 9 and emerging leadership roles in regional frameworks such as the CPTPP illustrate Japan's modern security awakening. As Japan strives to move past its imperialist wartime legacy and the security dilemma, its regional engagement and security activism may prove consequential for U.S. national security interests in the Indo-Pacific.

Approved for public release; distribution is unlimited -- Report documentation page. The opinions and conclusions expressed herein are those of the student author and do not necessarily represent the views of the U.S. Army Command and General Staff College or any other governmental agency. (References to these studies should include the foregoing statement.) -- Thesis approval page. 15 June 2018 -- Thesis approval page.

Master of Military Art and Science thesis approval page --Abstract -- Acknowledgements -- Table of contents -- Acronyms -- Illustrations -- Tables -- Chapter 1. Introduction -- Background -- Problem statement -- The research question -- Purpose -- Key terms and definitions -- Assumptions -- Scope -- Limitations and delimitations -- Significance -- Summary -- Chapter 2. Literature review -- Introduction -- Section I: U.S.-Japan security alliance -- Section II: strategic guidance (Japan) -- Section III: strategic guidance (U.S.) -- Section IV: Japan’s strategic security environment -- Section V: Japan’s capabilities -- Section VI: Japan-China rivalry -- Section VII: Japan’s frenemy – Republic of Korea -- Section VIII: Japan’s emerging partnerships with India, Australia, and ASEAN -- Section IX: literature review summary -- Chapter 3. Research methodology -- Phase one -- Phase two -- U.S. diplomatic objectives: advance American influence -- U.S. informational objectives: protect the American way of life -- U.S. military objectives: preserve peace through strength -- U.S. economic objectives: promote prosperity -- Phase three -- Chapter 4. Analysis -- Section I: DIME analysis (Japan) -- Diplomatic (Japan) -- Informational (Japan) -- Military (Japan) -- Section II: evaluation criteria (U.S. national security interests) -- U.S. diplomatic objectives -- U.S. informational objectives -- U.S. military objectives -- Section III: evaluation criteria analysis -- Section IV: summary -- Chapter 5. Conclusions and recommendations -- introduction -- Key findings -- Unexpected findings -- Recommendations for further study -- Recommendations for action -- Summary -- Glossary -- Bibliography.