Twenty-second Amendment to the United States Constitution
The Twenty-second Amendment (Amendment XXII) to the United States Constitution sets a limit on the number of times an individual is eligible for election to the office of President of the United States, and also sets additional eligibility conditions for presidents who succeed to the unexpired terms of their predecessors.
President-elect of the United States
The words "president elect" appear four times in the Constitution, and they didn't appear until 1933, when the Twentieth Amendment, which contained a provision addressing the unavailability of the president elect to take the oath of office on Inauguration Day, was ratified. Section 3 provides that if there is no president-elect on January 20, or the president-elect "fails to qualify", the vice president-elect would become acting president on January 20 until there is a qualified president. The section also provides that if the president-elect dies before noon on January 20, the vice president-elect becomes president. In cases where there is no president-elect or vice president-elect, the amendment also gives the Congress the authority to declare an acting president until such time as there is a president or vice president. At this point the Presidential Succession Act of 1947 would apply, with the office of the Presidency going to the speaker of the House of Representatives, followed by the president pro tempore of the Senate and various Cabinet officers.