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.
Twelfth Amendment to the United States Constitution
To prevent deadlocks from keeping the nation leaderless, the Twelfth Amendment provided that if the House did not choose a President before March 4 (then the first day of a Presidential term), the individual elected Vice President would "act as President, as in the case of the death or other constitutional disability of the President." The Twelfth Amendment did not state for how long the Vice President would act as President or if the House could still choose a President after March 4. Section 3 of the Twentieth Amendment, adopted in 1933, supersedes that provision of the Twelfth Amendment by changing the date upon which a new presidential term commences to January 20, clarifying that the Vice President-elect would only "act as President" if the House has not chosen a President by January 20, and permitting Congress to statutorily provide "who shall then act as President, or the manner in which one who is to act shall be selected" if there is no President-elect or Vice President-elect by January 20. It also clarifies that if there is no President-elect on January 20, whoever acts as President does so until a person "qualified" to occupy the Presidency is elected to be President.