United States v. Nixon

After the assassination of President John F. Kennedy and the succession of Vice President Lyndon B. Johnson to the presidency, Americans became concerned about the issue of presidential succession. For the next 14 months the vice-presidency remained vacant. Most Americans were shocked to learn that if Johnson, who had suffered a heart attack in 1955, died during 1964, John McCormack, the 73-year-old Speaker of the House of Representatives, would become president. Next in line was Carl Hayden, the 87-year-old president pro tempore of the Senate.

This situation was rectified on 10 February 1967 when the Twenty-fifth Amendment was ratified. This amendment allowed the president to nominate a new vice-president, who would take office after approval by a majority vote in each house of Congress. It also added provisions governing temporary presidential disability, specifying the circumstances and provisions by which a vice-president would become acting president.

The provisions for naming a new vice-president have only been invoked twice. In 1973 when President Richard M. Nixon selected Rep. Gerald Ford to replace Spiro T. Agnew; and in 1974 after Nixon resigned the presidency, Ford became president and Nelson A. Rockefeller of New York was chosen as the new vice president.