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.
2008 United States presidential election
Not only was the 2008 election the first time since 1952 that neither the incumbent president nor the incumbent vice president was a candidate in the general election, but it was also the first time since the 1928 election that neither sought his party's nomination for president; as Bush was term-limited from seeking another nomination, the unique aspect was Vice President Cheney's decision not to seek the Republican nomination. The 2008 election was also the third presidential election since 1896 in which neither the incumbent president, the incumbent vice president, nor a current or former member of the incumbent president's Cabinet won the nomination of either major party the others being 1920 and 1952. With no members of the Bush administration emerging as major contenders for the Republican nomination, the Republican race was as open as the Democratic race.Immediately after the 2006 midterm elections, media pundits began speculating, as they did about the Democrats, about potential Republican candidates for President in 2008. In November 2006, Former New York City Mayor Rudolph Giuliani led in the polls, followed closely by Arizona Senator John McCain. The media speculated that Giuliani's pro-choice stance on abortion and McCain's age and support of the unpopular Iraq War would be detriments to their candidacies. Giuliani remained the frontrunner in the polls throughout most of 2007, with McCain and former Tennessee Senator Fred Thompson fighting for second place. Arkansas Governor Mike Huckabee, Giuliani, Former Massachusetts Governor Mitt Romney, and Texas Representative Ron Paul announced their candidacies on January 28, February 5, February 13, and March 12, respectively. McCain officially announced his candidacy on March 1, 2007, after several informal announcements. In the third quarter of 2007, the top four GOP (Republican) fundraisers were Romney, Giuliani, Thompson, and Ron Paul. MSNBC's Chuck Todd christened Giuliani and John McCain the front runners after the second Republican presidential debate in early 2007.