History of the United States (1964–1980)
The growing Watergate scandal was a major disaster for Nixon, eroding his political support in public opinion and in Washington. However he did manage to secure large-scale funding for South Vietnam, much of which was wasted. The United States withdrew its troops from Vietnam before the Paris Peace Accords in 1973. However, Watergate resulted in significant Democrat gains in the 1974 midterm elections and when the new 94th Congress convened the following January, it immediately voted to terminate all aid to South Vietnam in addition to passing a bill forbidding all further US military intervention in Southeast Asia. President Ford was against this, but as Congress had a veto-proof majority, he was forced to accept. South Vietnam rapidly collapsed as the North invaded it in force, and Saigon fell to the NVA on April 30, 1975. Later nearly one million Vietnamese managed to flee to the U.S. as refugees. The impact on the U.S. was muted, with few political recriminations, but it did leave a "Vietnam Syndrome" that cautioned against further military interventions anywhere else. Nixon (and his next two successors Ford and Carter) had dropped the containment policy and were not willing to intervene anywhere.
Gulf of Tonkin Resolution
The administration of President Richard Nixon, which took office in January 1969, initially opposed repeal, warning of "consequences for Southeast Asia [that] go beyond the war in Vietnam". In 1970 the administration began to shift its stance. It asserted that its conduct of operations in Southeast Asia was based not on the resolution but was a constitutional exercise of the President's authority, as Commander in Chief of U.S. military forces, to take necessary steps to protect American troops as they were gradually withdrawn (the U.S. had begun withdrawing its forces from Vietnam in 1969 under a policy known as "Vietnamization").