A Who's Who of 2016 US Presidential Contenders

Washington, United States: Americans troop to the polls to elect the successor to President Barack Obama one year from Sunday.

One of the following men or women, listed here according to their current standing in national polls, will be the White House's next occupant.

Three Democrats

Hillary Clinton, age 68: She has served as first lady, US senator from New York, and Barack Obama's first secretary of state, after she lost their 2008 nomination battle. Her poll numbers tumbled this year amid distrust over her handling of an email scandal, but she has regained primacy in the race.

Bernie Sanders, 74: The independent US senator from Vermont is a self-described democratic socialist who calls for a "political revolution" in America. He draws large crowds to his rallies, inspiring leftist Democrats with his reproach of billionaires and demands for Wall Street reform.

Martin O'Malley, 52: The ex-Baltimore mayor and Maryland governor has spent decades in public service but has yet to make a mark nationally. He has called for new blood in US politics, hitting the Bush-Clinton network by saying the presidency "is not a crown to be passed back and forth."

Fifteen Republicans

Donald Trump, 69: The opinionated billionaire real estate tycoon has also been a brusque TV personality. His politically incorrect campaign has resonated with millions, but he angered establishment Republicans and potentially crucial Hispanic voters by calling some Mexican immigrants rapists.

Ben Carson, 64: Like Trump, this retired neurosurgeon has never held public office, but the soft-spoken conservative has surged in the polls.
He is the only African-American in the race, and while he preaches tolerance, he has raised eyebrows with controversial comments about gays, Nazis and slavery.

Marco Rubio, 44: A son of Cuban immigrants, the senator from Florida speaks fluent Spanish and aims to head the next generation of conservative leadership. He advocates muscular foreign policy and US military re-engagement in the world, and notably called Clinton a "liar" in the last Republican debate.

Ted Cruz, 44: Also a senator and also Cuban-American, the flagbearer of arch-conservative causes is a former Texas solicitor general and an excellent orator. While he serves in the US Senate, he is widely seen as an outsider and routinely breaks with party leadership.

Jeb Bush, 62: Florida's ex-governor is the son and brother to two presidents, and was the early favorite. He is the Republican most open to immigration reform, and has raised vast sums of money, but he is struggling to regain voter interest.

Carly Fiorina, 61: Hewlett-Packard's former CEO spent millions from her personal fortune in an unsuccessful 2010 Senate bid. The only Republican woman candidate vaulted into the top tier in September after a strong debate performance.

John Kasich, 63: The governor of Ohio is a fiscal conservative and social moderate running a politically crucial state. He has national security experience from his years in Congress.

Rand Paul, 52: The first-term US senator from Kentucky represents the party's libertarian wing. A certified ophthalmologist, his election strategy includes drawing support from minorities. He advocates criminal justice reform and opposes raising the debt ceiling.

Mike Huckabee, 60: The former Arkansas governor, preacher and television host is making his second presidential run. The defender of religious liberty hopes to capitalize on his rural evangelical following.

Chris Christie, 53: The blunt-talking governor of mainly Democratic New Jersey wants to reform the tax system, broaden national energy policy and "re-establish American leadership." He is a former federal prosecutor.

Five lower-polling Republicans are also running: ex-Senator Rick Santorum, Louisiana Governor Bobby Jindal, Senator Lindsey Graham, former New York governor George Pataki and former Virginia governor Jim Gilmore.

Wisconsin Governor Scott Walker and former Texas governor Rick Perry dropped out of the race in September.