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.
2016 Democratic Party presidential primaries
In the weeks following the re-election of President Obama in the 2012 election, media speculation regarding potential candidates for the Democratic presidential nomination in the 2016 presidential election began to circulate. The speculation centered on the prospects of Clinton, then-Secretary of State, making a second presidential bid in the 2016 election. Clinton had previously served as a U.S. Senator for New York (2001–09) and was the First Lady of the U.S. (1993–2001). A January 2013 "Washington Post"–ABC News poll indicated that she had high popularity among the American public. This polling information prompted numerous political pundits and observers to anticipate that Clinton would mount a second presidential bid in 2016, entering the race as the early front-runner for the Democratic nomination. From the party's liberal left wing came calls for a more progressive candidate to challenge what was perceived by many within this segment as the party's establishment. Elizabeth Warren quickly became a highly touted figure within this movement as well as the object of a draft movement to run in the primaries, despite her repeated denials of interest in doing so. The MoveOn.org campaign 'Run Warren Run' announced that it would disband on June 8, 2015, opting to focus its efforts toward progressive issues. The draft campaign's New Hampshire staffer, Kurt Ehrenberg, had joined Sanders' team and most of the remaining staffers were expected to follow suit. Given the historical tendency for sitting vice presidents to seek the presidency in election cycles in which the incumbent president is not a candidate, there was also considerable speculation regarding a potential presidential run by incumbent Vice President Joe Biden, who had previously campaigned for the Democratic presidential nomination in the election cycles of 1988 and 2008. This speculation was further fueled by Biden's own expressions of interest in a possible run in 2016. However, on October 21, 2015, speaking from a podium in the Rose Garden with his wife and President Obama by his side, Biden announced his decision not to enter the race, as he was still dealing with the loss of his son, Beau, who died weeks earlier at the age of 47.