In 1973, the USAF was authorised by Presidential authority to continue the bombing of Vietnam after the expiration of the deadline laid down by the US Congress because the Case-Church Amendment had been vetoed by Richard Nixon.
By Ed, Scott Palter and Amnah KhanSoon enough a fresh NVA Offensive demonstrated that Nixon was correct in sustaining the pressure of the bombing campaign because the policy of Vietnamisation was insufficient in itself for the South to survive. Instead he sent supplies under his authority as Commander-in-Chief and ordered new B-52 strikes.
Of course this truth had been self-evident from the moment that Le Duc Tho the North Vietnam Negotiator of the Paris Peace Accords had declined the award of a Nobel Peace Prize, saying that a true peace did not yet exist. Ironically, within months Nixon himself would himself be struggling to survive.
Whether Nixon had planned it or not the Watergate Crisis was profoundly affected by the resumption of hostilies in Vietnam. An issue from legalistic squabbles about abuse of power had been transformed into full blown constitutional crisis about the war powers of the Presidency. As a result, it was harder to get Republican votes for impeachment, leaving Nixon in office as the House kept impeaching him over and over 1975-6 while the Senate acquitted him by a few votes.