Demand for trilateral cooperation between the United States, South Korea, and Japan is on the rise. However, political willingness and capacity for trilateral cooperation are declining, especially given recent diplomatic and economic tensions between South Korea and Japan. “Strategic Estrangement Between South Korea and Japan as a Barrier to Trilateral Cooperation,” a comprehensive report by Dr. Cheol Hee Park, nonresident senior fellow in the Atlantic Council’s Asia Security Initiative, examines shifting perspectives on trilateral cooperation, the layers of conflict between South Korea and Japan, and the role of the United States and concludes by providing concrete policy recommendations for enhancing prospects for trilateral cooperation moving forward.