Scholars and policy analysts from the United States, Japan, and South Korea met in Tokyo Aug. 12, 2010 to discuss the security environment in Northeast Asia and opportunities for enhanced cooperation among US alliance partners in Northeast Asia and beyond. Throughout the discussions, the changing status of China as a rising power in the region and the increasing unpredictability of North Korea shaped threat perceptions while the difficult and contested history between Korea and Japan moderated expectations for increased trilateral cooperation among alliance partners. While trilateral cooperation among the allies in Northeast Asia remains an attractive prospect, care must be taken to avoid creating the perception that its purpose is to “encircle” China.