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.
South Vietnam
After promising not to do so during the 1964 election campaign, in 1965 President Lyndon B. Johnson decided to send in much larger numbers of combat troops, and conflict steadily escalated. The NLF ceased to be an effective fighting organization after the Tet Offensive in 1968 and the war was largely taken over by regular army units of North Vietnam. Following American withdrawal from the war in 1973, the South Vietnamese government continued fighting until its unconditional surrender to the Viet Cong on 30 April 1975, the day of the surrender of Saigon. North Vietnam controlled South Vietnam under military occupation, while the Provisional Revolutionary Government of the Republic of South Vietnam, which had been proclaimed in June 1969 by the NLF, became the nominal government. The North Vietnamese quickly moved to marginalise non-communist members of the PRG and integrate South Vietnam into the communist North. The unified Socialist Republic of Vietnam was declared on 2 July 1976. The Embassy of the Republic of Vietnam in Washington donated 527 reels of South Vietnamese-produced film to the Library of Congress during the embassy's closure following the Fall of Saigon, which are in the Library to this day.