This paper examines the development of a new global order in Northeast Asia and its characteristics with a focus on U.S.-China relations and the limits to cooperation among Korea, China and Japan. The authors emphasize the need to build a multilateral security cooperation system in the region to complement the existing bilateral security architecture. Highlighting the necessity of cooperation in two triangular groups, Korea-U.S.-Japan and KoreaChina-Japan, particulary with respect to resolving North Korea's nuclear problem, the paper argues that mini-multilateral or minilateral arrangements can be a useful vehicle to create efficient and promising cooperation dynamics in the region.