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.
Paris Agreement
On August 4, 2017, the Trump administration delivered an official notice to the United Nations that the U.S. intends to withdraw from the Paris Agreement as soon as it is legally eligible to do so. The formal notice of withdrawal cannot be submitted until the agreement is in force for 3 years for the US, in 2019. In accordance with Article 28, as the agreement entered into force in the United States on 4 November 2016, the earliest possible effective withdrawal date for the United States is 4 November 2019. If it chooses to withdraw by way of withdrawing from the UNFCCC, notice could be given immediately (the UNFCCC entered into force for the US in 1994), and be effective one year later.