Answer :
President Nixon's alleged abuse of authority in the Vietnam War led to the War Powers Resolution of 1973. Richard Nixon had conducted secret bombings in Cambodia during the Vietnam War without asking Congress and this had been leaked to Washington DC. He ultimately did not want to enact the War Powers Resolution but his veto was overrode by Congress by 2/3 of the vote, which is what you need to override a veto and enact a law.
