Southeast Asia in United States policy fell from a region of high priority during the Vietnam war to become, after the fall of Indochina, an area of relatively minor interest. For the United States, Southeast Asia evoked memories of misperception, intensified over-commitment, and simplistic assumptions that characterized the American effort to defeat local Vietnamese national communism. Since the formulation of the Nixon doctrine of disengagement in 1969, United States policy towards Southeast Asia has been undergoing a process of long-term readjustment in recognition of the exaggerated significance that the region had assumed in American thinking. The fall of Saigon in April 1975 was a major stimulus to this readjustment as it gave the Americans compelling reasons to anticipate a reassertion of Soviet influence in the region. Successive American administrations attempted to place the region in a wider global context to avoid the dangers of extreme reaction to local national communism while developing the flexibility to coordinate a response to the Soviet Union at a global level. The main concern of American policy was to remove the basis for direct United States involvement in the region in a way that would satisfy post-Vietnam war public and congressional opinion and the demands of strategic planners for greater freedom of manoeuvre against the Soviet Union.