Parallels between America's role in East Asia and its involvements in Europe might seem far-fetched. Asia's geography and history are enormously different, there is no regional organization in any way comparable to the European Union, the area is not a zone of peace, conflict among its leading states remains a potential risk, and there is nothing remotely resembling NATO as a formal multilateral alliance binding the United States to the region's security and the regional states to one another. Yet, as in Europe, the United States plays a unique stabilizing role in Asia that no other country or organization is capable of playing. Far from being a source of tension or instability, this presence tends to reduce competition among regional powers and to deter armed conflict. Disengagement, as urged by some critics of American primacy, would probably lead to more dangerous competition or power-balancing among the principal countries of Asia as well as to a more unstable security environment and the spread of nuclear weapons.