Story highlights Hillary Clinton is tops in Iowa with 53% support from registered Democrats

Vice President Joe Biden finished second with 15%

The GOP field is more crowded, with almost 10 politicians in the single digits

Former Gov. Mike Huckabee leads the Republican field with 21%

Hillary Clinton is heading to Iowa as the politician that most Democrats would choose as their 2016 presidential nominee.

According to a new CNN/ORC International poll , 53% of all registered Democrats contacted in Iowa said they would support Hillary Clinton if the 2016 caucuses were held today. That number far outpaces the 15% that would opt for Vice President Joe Biden, 7% who would choose Sen. Elizabeth Warren and 5% who would pick Sen. Bernie Sanders.

Clinton will be visiting Iowa for the first time in six years on Sunday when she headlines the last Harkin Steak Fry. Biden, likewise, will be in the state Wednesday to speak at a liberal Catholic event in Des Moines.

Although Clinton tops Biden with men and women, there is a noticeable gender split between the two politicians. Sixty-three percent of women favor Clinton, compared with Biden's 10%. With men, however, Biden is drawing 21% support -- a number more than twice his support among women.

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On the Republican side, Mike Huckabee nearly laps the field with 21% of all registered Republicans contacted in the poll saying they would support the former Arkansas governor if the 2016 Iowa caucuses were held today.

Paul Ryan is second with 12%, and there is a cadre of politicians -- including Sen. Rand Paul, former Florida Gov. Jeb Bush and New Jersey Gov. Chris Christie -- with support in the single digits.

Huckabee and Ryan are getting similar support with men -- 15% and 16%, respectively -- but it is with women that the former Arkansas governor jumps ahead of the congressman.

Twenty-seven percent of registered Republican women polled said they would pick Huckabee, compared with 8% who choose Ryan.

As the first-in-the-nation caucus state, Iowa is critically important to presidential hopefuls and can make or break a campaign.

With almost two years until the 2016 presidential election and a little over a year before the Iowa caucuses, most Republicans and Democrats polled have openly admitted that they are toying with the idea of running for president.

The CNN/ORC poll was conducted September 8-10, with 1,013 Iowa adults -- 608 likely voters -- questioned by telephone. The survey's overall sampling error is plus or minus 4 percentage points.