Changing security dynamics on the Korean Peninsula are prompting the Republic of Korea (ROK) to reexamine its defense strategy and adjust its military capabilities and investment priorities. North Korea’s growing missile arsenal and asymmetric defense strategy, along with China’s rapid military modernization, present unique challenges to South Korean and American efforts to maintain stability on the Korean Peninsula and in the broader region. To identify how the ROK can best align its defense strategy and capabilities, and to clarify the alliance division of labor between the ROK and the United States, the Center for Strategic and Budgetary Assessments (CSBA) hosted a virtual roundtable discussion and decision-making exercise. The event, held on March 18-19, 2021, convened U.S. and South Korean defense analysts to debate the scenarios and objectives that should most influence Seoul’s defense planning, capability and capacity requirements, and investment decisions over the next decade.