Millennials' Favorite Presidential Candidates: Hillary Clinton, Elizabeth Warren, and... Ben Carson?

A new poll shows young voters are just as mixed up about the emerging Republican presidential field as anyone else.

A report released by the Harvard Institute of Politics Wednesday took the temperature of voters aged 18 to 29, otherwise known as millennials.

The report found that 55 percent of millennials say they prefer a Democrat to win the presidency in 2016, versus 40 percent who would prefer to see a Republican in the White House. Among millennials who identify as politically independent, that gap narrows, with 46 percent supporting Democrats and 43 percent supporting Republicans.

In a call with reporters, the Institute of Politics' John Della Volpe pointed out that there is an eight-way statistical tie for millennials who support Republican primary candidates. One of the most surprising results of the report was that Dr. Ben Carson, a retired neurosurgeon, was leading a crowded pack of otherwise preferred Republican candidates, with 10 percent of respondents saying Carson would be their first choice in a Republican primary.

The margin of error is 2.4 percent, so it's unfair to say that Carson definitively has better millennial support than Sen. Rand Paul of Kentucky, who got 8 percent support. But Carson, Paul, former Florida Gov. Jeb Bush, and former Arkansas Gov. Mike Huckabee all enjoy a similar level of support from young respondents. Carson will announce his presidential campaign in Detroit on May 4. The next day, Huckabee will make his own announcement in his hometown of Hope, Arkansas.

Each of them represents a different flavor of the Republican Party: Bush, the establishment Republican; Huckabee, the evangelical conservative; Paul, the libertarian-minded upstart; and Carson, the charismatic political outsider.

On the Democratic side, Hillary Clinton enjoys broad support among millennial voters: 47 percent of respondents support Clinton over Massachusetts Sen. Elizabeth Warren, Vice President Joe Biden, former Maryland Gov. Martin O'Malley, former Sen. Jim Webb of Virginia, or Sen. Bernie Sanders of Vermont. Still, her potential primary challengers can take some hope: 28 percent of respondents said they don't know which Democrat would be their first choice in 2016.

Age is an important factor in distinguishing the Republican candidates' appeal, in an election year where the national party has called youth outreach a priority. A recent Quinnipiac poll found that young voters prefer Clinton over virtually all of her Republican opponents, but some of those Republicans fared better among millennials when matched up against her.

New Jersey Gov. Chris Christie, Sen. Marco Rubio of Florida, and Paul enjoyed the smallest gap between voters aged 18 to 34 who said they would vote for Clinton over them—a roughly 10 percent gap between pro-Clinton voters and others. The same poll found that Huckabee, Bush, and Sen. Ted Cruz of Texas would have the hardest time making up ground among young voters in a matchup against Clinton.

Other findings from the Harvard IOP poll:

Fully 57 percent of millennials support the United States sending ground troops to combat the Islamic State of Iraq and Syria. In March, a Quinnipiac University poll found that 62 percent of American voters support boots on the ground to fight ISIS.

Three out of four millennials believe global warming is a fact, not just a theory. On other environmental issues, millennials are virtually split on the Keystone XL pipeline, while a majority, 58 percent, oppose the use of fracking in United States.

84 percent of millennials say children should be vaccinated before entering school.

Millennials are split (49 percent/49 percent) on whether they are confident in the U.S. judicial system's ability to "fairly judge people without bias for race and ethnicity." That confidence erodes among black and Hispanic respondents, the majority of whom said they have not much or no confidence in the justice system.

As protests and riots continue in Baltimore in the wake of Freddie Gray's death, 49 percent of the respondents (who were polled before Gray's death and the protests it provoked) said that they support similar protests seen in Ferguson, Missouri, and New York City. However, just 39 percent of respondents said they believe the protests will be very or somewhat effective in making meaningful change to law enforcement.

80 percent of millennials said requiring police officers to wear body cameras on duty would be effective for curbing racial inequality in the justice system.

On Wednesday morning, just after the poll results were published, Clinton tweeted, "We should make sure every police department in the country has body cameras to record interactions between officers on patrol and suspects."

Disclosure: National Journal's Ron Fournier sits on the Harvard Institute of Politics' advisory board.