• My project assesses the logic and efficacy of US. strategy toward the Asia-Pacific since the Cold War's end, with a particular focus on the role of Japan as Washington's most important regional partner—as security ally, economic power, and fellow democracy. A rapidly changing world and region demand an analysis that is theoretically and empirically-grounded, while simultaneously retrospective and forward-looking. New challenges and new opportunities also demand a major transformation of U.S. strategy. • Or do they? Have regional circumstances changed such that major strategic recalibrations are necessary in Washington and Tokyo? To judge where we should go, we must first appreciate more fully how we got here. Historical baselining is a precondition for measuring change, and for sober evaluations about whether changing strategic contexts necessitate the fundamental "reset" increasing observers now advocate. The questions my project seeks to answer: what have been the core logics informing U.S. Asia-Pacific strategy and the U.S-Japan alliance's evolution since 1991? With the benefit of hindsight, have associated policies achieved intended objectives? Looking forward, what lessons can be drawn, and what adjustments are needed to ensure continued peace and deepening prosperity? What role should Washington and Tokyo play? Directly relavant to contemporary policy debates, answers to these questions have significant implications for major international relations theories (e.g., rising powers; alliance dilemmas). • My project aims to make two major contributions: First, my goal is to produce a "one-stop shop" history of the evolution of U.S. Asia-Pacific strategy in the quarter-century since the Cold War's end. A theoretically-informed, historical study of U.S. and Japanese decision-making at major policy inflection points is conspicuously absent from the literature, and sorely needed to fill important gaps in theoretical and policy debates on the region' past, present, and future. Second, my project will identify—explicitly—the assumptions and causal logic informing major policy decisions in Washington and Tokyo that in aggregate constitute the core of U.S. strategy. I am particularly interested in making explicit the (heretofore implicit) theoretical rationale driving Washington's and Tokyo's effort to engage China as a "responsible stakeholder"—an approach unprecedented "great power vs. rising power" history and one whose assumed causal mechanisms the literature does a poor job of capturing. In contrast to the overwhelmingly descriptive literature my goal is to systematically unpack the logic and assumptions informing associated policies, while simultaneously subjecting to an empirical test widespread (usually dedutive, often ahistorical) theoretical claims about the forces driving conflict and cooperation in contemporary East Asia. • I aim to examine existing policy origins and in the process generate a forward-looking history of the logic and evolution of post-Cold War U.S. Asia-Pacific strategy—especially the U.S. alliance system and Japan's role in it. The project will generate new knowledge and original synthesis to inform U.S.-Japan policy debates, and deepen public awareness. Finally, my project will draw lessons about whether and where regional vicissitudes necessitate policy adjustments. At this historical moment, path dependency based on existing assumptions and theories may, paradoxically, be the riskiest course, undermining the past quarter-century's achievements.