Vice President of the United States the Twenty-fifth Amendment established a procedure for filling such a vacancy: This procedure has been implemented twice since the amendment came into force. The first instance occurred in 1973 following the October 10 resignation of Spiro Agnew, when Gerald Ford was nominated by President Richard Nixon and confirmed by Congress. The second occurred 10 months later following Ford's August 9, 1974 accession to the presidency upon Nixon's resignation, when Nelson Rockefeller was nominated by President Ford and confirmed by Congress. Had it not been for this new constitutional mechanism, the vice presidency would have remained vacant after Agnew's resignation and
Acting President of the United States thirty-five years old; and be a resident in the United States for at least fourteen years. A person who meets these requirements may still be constitutionally disqualified from the presidency under any of the following conditions: Article II, Section 1, Clause 6 makes the vice president first in the line of succession. It also empowers Congress to provide by law who would act as president in the case where neither the president nor the vice president were able to serve. Two constitutional amendments elaborate on the subject of presidential succession and fill gaps exposed over time in the original provision: