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.
Cambodian–Vietnamese War
The end of the Cambodian conflict also brought an end to the ASEAN-imposed trade and aid embargo which had been in place since 1979. In January 1990, Thai Prime Minister Chatichai Choonhavan publicly voiced his support for Vietnam, and the rest of Indochina, to gain admission into ASEAN. In the period between late 1991 and early 1992, Vietnam restored relations with several member nations of ASEAN. As a result, between 1991 and 1994, investments from ASEAN countries made up 15 percent of direct foreign investment in Vietnam. Aside from the obvious economic benefits, ASEAN also provided a peaceful environment that guaranteed Vietnam's national security against foreign threats in the post-Cold War era, when Soviet aid was no longer available. Thus, on 28 July 1995, Vietnam officially became the seventh member of ASEAN, after leading ASEAN officials invited Vietnam to join at the ASEAN Ministerial Meeting in Bangkok in 1994. Then, in August 1995, the U.S. Liaison Office in Hanoi was upgraded to Embassy status, after U.S. President Bill Clinton announced a formal normalisation of diplomatic relations with Vietnam on 11 July 1995, thereby ending Vietnam's isolation from the United States.