Twenty-second Amendment to the United States Constitution
Since coming into force in 1951, the amendment has applied to six presidents who have been elected twice: Dwight D. Eisenhower, Richard Nixon, Ronald Reagan, Bill Clinton, George W. Bush, and Barack Obama. It has also applied to two who entered office intra-term due to their predecessor's death or resignation: Lyndon B. Johnson and Gerald Ford. Johnson became president in November 1963, following the assassination of John F. Kennedy, served out the final of Kennedy's term, and was elected to a full four-year term in 1964. Four years later, he briefly ran for a second full term, but withdrew from the race during the party primaries. Had Johnson served a second full term – through January 20, 1973 – the total length of his presidency would have been ; as it happened, Johnson died two days after this date. Gerald Ford, who became president in August 1974 following the resignation of Richard Nixon, served the final of Nixon's term, and attempted to win a full four-year term in 1976, but was defeated by Jimmy Carter. Johnson was eligible to be elected to two full terms in his own right, as he had served less than two years of Kennedy's unexpired term, whereas Ford was eligible to be elected to only one full term, as he had served more than two years of Nixon's unexpired term.
George Allen (American politician)
Barred by term limits from seeking reelection to a second term in 1997, he worked in the private sector until the 2000 election in which he ran for the United States Senate, defeating two-term Democratic incumbent Chuck Robb. Allen ran for reelection in the 2006 election, but after a close and controversial race, he was defeated by Democratic former U.S. Secretary of the Navy Jim Webb. When Webb decided to retire, Allen ran for his old seat again in the 2012 election but was defeated again, this time by Democratic former Governor Tim Kaine. Allen now serves on the Reagan Ranch Board of Governors of Young America's Foundation, where he is a Reagan Ranch Presidential Scholar.