Twenty-second Amendment to the United States Constitution
The amendment prohibits any individual who has been elected president twice from being elected again. Under the amendment, an individual who fills an unexpired presidential term lasting greater than two years is also prohibited from winning election as president more than once. Scholars debate whether the amendment prohibits affected individuals from succeeding to the presidency under any circumstances or whether it only applies to presidential elections.
President of the United States
Since the amendment's adoption, five presidents have served two full terms: Dwight D. Eisenhower, Ronald Reagan, Bill Clinton, George W. Bush, and Barack Obama. Both Jimmy Carter and George H. W. Bush sought a second term, but were defeated. Richard Nixon was elected to a second term, but resigned before completing it. Lyndon B. Johnson, having held the presidency for one full term in addition to only 14 months of John F. Kennedy's unexpired term, was eligible for a second full term in 1968, but withdrew from Democratic Primary. Additionally, Gerald Ford, who served out the last two years and five months of Nixon's second term, sought a full term, but was defeated by Jimmy Carter in the 1976 election.