Washington, Aug 2 American voters looking for a new tenant for the White House are spoiled for choice with 22 candidates, five Democrats and 17 Republicans, including long shot Indian-American Bobby Jindal in the 2016 presidential race.

Leading the Democratic pack is Hillary Clinton, 67, former First Lady and Secretary of State with more than half the party voters backing her but independent socialist senator Bernie Sanders, 73, is fast closing the gap with 17 percent in recent polls.

And if Vice President Joe Biden, 72, too jumps into the fray as speculated, it could really stir the Democratic pot amid questions being raised afresh about Clinton\'s use of private email and her handling of the 2012 attack on an American diplomatic compound in Benghazi, Libya.

Biden, according to a New York Times report has been \"talking to friends, family and donors about jumping in\" to challenge Clinton in Iowa and New Hampshire, the first two nominating states.

Three other candidates, Martin O\'Malley, 52, former governor of Maryland and mayor of Baltimore, Lincoln Chafee, 62, former senator and governor of Rhode Island and Jim Webb, 69, former senator and Vietnam veteran, haven\'t really excited the voters any so far.

While the Democrats have yet to announce the dates of six official televised primary debates, knives are out in the Republican camp to get on the main stage for the first of the nine official debates scheduled for Aug 6 in Cleveland Ohio.

With hosts Fox News limiting the main debate to top ten in five most recent national primary polls as of 5 p.m. on Tuesday, respected election site fivethirtyeight has picked up top eight candidates who are most likely to make it.

They include celebrity real estate mogul Donald Trump, who has shot into the lead with his promise to make America great again overtaking establishment favourite Jeb Bush, 62, former Florida governor and son of a former president and brother of another.

Others likely to make it thanks to their fairly consistent performance in the polls are Wisconsin governor Scott Walker, 47 and Arkansas governor Mike Huckabee, 59, who has courted controversy by comparing the Iran nuclear deal to \"marching [Israel] to the door of the oven.\"

So are conservative firebrand Cuban American Texas senator Ted Cruz, 44, libertarian conservative Kentucky senator and physician Rand Paul, 52, Cuban American Florida senator Marco Rubio, 44, and author and neurosurgeon Ben Carson, 63.

New Jersey governor Chris Christie, 52, Ohio governor John Kasich, 63, Rick Perry, 65, who served as Texas governor from 2000 to 2015 and former Pennsylvania senator Rick Santorum, 57, are considered bubble candidates for the Aug 6 debate. Any two of them could make it.

But Louisiana governor Bobby Jindal, 44, a former vice chairman of the Republican Governors Association, former HP chief executive Carly Fiorina, 60, former Virginia governor Jim Gilmore, 62, South Carolina Lindsey Graham, 60, and former New York governor George Pataki, 70, would most ikely miss it.

Only Jindal is polling above 1 percent, and no one in this group has got more than 2 percent in any of the last seven individual live-interview polls, according to fivethirtyeight.

They all face the prospect of being relegated to a secondary forum at 5 p.m. before the prime time main feature.

But the polling day - Tuesday, Nov 8, 2016, - when the voters go to chose their president in an indirect election is still a long way off with a gruelling primary process set to start only in February.

It\'s thus hard to speculate who would finally emerge as Democratic and Republic candidates at their national conventions at Philadelphia, Pennsylvania and Cleveland, Ohio respectively in July next year.

And there could well be a third party candidate jumping in as a wild card.

US presidential race: Voters spoiled for choice