While some likely contenders have been positioning themselves for a White House bid for months, others are still evaluating their chances and many could wait until early 2015 to make a decision.
Here are a few of the possible White House contenders in 2016:
The former secretary of state and first lady, who lost an acrimonious Democratic presidential nominating battle to Barack Obama in 2008, is the consensus frontrunner and holds a large lead in preliminary polls over all potential Democratic challengers. Clinton, 67, has not said whether she plans to run, but supporters have built a national campaign structure to await her candidacy, including a pair of high-profile super PACs. Since leaving the State Department in 2013, the wife of former president Bill Clinton has been giving a series of paid speeches and campaigning for Democrats.
The vice president, 71, has served alongside Obama since 2008. Before that, the outspoken foreign policy expert served six terms as a senator from Delaware. Biden, who mounted losing presidential bids in 1988 and 2008, has hinted he is considering running again.
The Maryland governor, 51, will leave office at the end of 2014. He spent much of the last year campaigning for Democrats around the country, particularly in New Hampshire and Iowa, the first two states with presidential nominating contests.
The first-term Massachusetts senator has so far brushed aside pleas from liberal supporters that she run for president, but the former Harvard Law School professor and persistent Wall Street antagonist, 65, is still a favorite of progressive activists.
Vermont’s independent senator was a frequent visitor to Iowa and New Hampshire during the 2014 election cycle. The self-described socialist, 73, has said he might run for president – a move many political observers believe would be designed to push Clinton to the left.
The Kentucky senator, 51, has not been shy about his White House ambitions, hinting he will follow his father Ron Paul’s path and run for president. While the elder Paul was a perennial loser in Republican primaries, his libertarian-leaning son has made an effort to broaden his appeal with appearances before young and minority audiences that are not normally considered fertile ground for Republicans.
The New Jersey governor, 52, has fought hard to cultivate an image as a brash bipartisan dealmaker from a blue state. His potential candidacy suffered a setback with the January 2014 “Bridgegate” scandal, but he has used his status as head of the Republican Governors Association to raise money and campaign for candidates in 2014, gathering favors along the way.
The 2012 Republican vice presidential nominee is a favorite of Wall Street donors, but many political observers believe Ryan’s real ambition is to rise within the U.S. House of Representatives where he has served since 1999. The 44-year-old Wisconsin congressman campaigned for Republicans in 2014, but he has not said much about his plans.
Is the country ready for a third Bush president? The former Florida governor, the brother of one president and the son of another, has been testing the waters of a White House bid. But his moderate positions on immigration, education and other issues mean Bush, 61, is not popular among many conservatives.
Rubio, 43, was swept into the Senate in the Tea Party wave of 2010. The Floridian has since gained a reputation as a national figure, but he has been fighting to strengthen his ties to conservatives after drawing their ire in 2013 for helping lead a failed push for comprehensive immigration reform.
Cruz, 43, is the Texan Tea Party favorite who championed the government shutdown of October 2013 because of his staunch opposition to Obama’s healthcare law. Cruz has gathered influence in Washington despite his firebrand status, and his national popularity among conservatives has many of his supporters excited for 2016.
The long-serving Texas governor crashed out of 2012’s nominating process after an embarrassing debate performance in which he forgot the third government agency he proposed to eliminate. But Perry, 64, has spent the time since then preparing himself for a run and promoting his state’s economic growth.
Frequently mentioned as a vice-presidential contender, Louisiana’s governor Jindal has made it clear he is eyeing a White House run. The former Rhodes scholar, 43, came under fire in early 2013 when he warned his party it needed to “stop being the stupid party.”
Ex-Arkansas governor Huckabee ran unsuccessfully in 2008 and refused to run in 2012, despite his popularity with influential evangelical leaders and voters. But the 59-year-old with strong early poll numbers has suggested he could run again in 2016.
A favorite of the Christian right, the former Pennsylvania senator, 56, won the Iowa caucuses in 2012 and was an active campaigner in the 2014 election cycle.
The former Alaska Governor divides opinion between the Tea Party faithful and party moderates however; she does have “Rock Star” status among her loyal base. Don’t dismiss her just yet.