[2] When it became apparent that the amendment would pass, President Richard Nixon and Secretary of State Henry Kissinger,[3] lobbied frantically to have the deadline extended.

[4] However, under pressure from the extreme scrutiny of Watergate, Republicans relented on support for South Vietnam, and the amendment passed the United States Congress in June 1973 by a margin of 325–86 in the House, 73–16 in the Senate.

[5][6] Both of these margins for the amendment's passage were greater than the two-thirds majority required to override a presidential veto,[5] and Nixon signed it on July 1, 1973.

The last U.S. forces had been withdrawn from South Vietnam in March 1973 pursuant to the Paris Peace Accords.

US bombing in Cambodia, the only form of US combat action that had continued in any part of Indochina after April, ended on August 15, 1973, the deadline set by the amendment.