Important themes in the history of international relations in Asia Pacific during this period included the new international roles of China and Japan, the position adopted by the United States, the Cold War conflicts in the 1950 and 1960s, decolonization in Southeast Asia, the Sino-Soviet conflict, the Sino-American rapprochement of the 1970s, the emergence of Southeast Asian regionalism, and postcolonial conflicts in Southeast Asia. To appreciate the significance of these various themes and their interrelationships it will be helpful to focus on three key phases: the late 1940s, the 1950s, and the 1970s and 1980s.