MANCHESTER, NH— Hillary Clinton emerged from the Iowa caucuses with a razor-thin victory over Bernie Sanders — and a new round of nervous second-guessing from supporters.

Topping the list of concerns is Clinton’s disadvantage with young voters, a crucial Democratic constituency that overwhelmingly sided with Sanders. Clinton supporters are also worried that the campaign is still struggling with a muddled message, a problem in her failed 2008 White House bid.

The campaign underperformed by its own expectations. In the hours before the caucuses began, aides privately told supporters they expected her to win by about five points.

The final tally put Clinton ahead by less than three-tenths of 1 percent.

Big challenges await Clinton as the race moves to New Hampshire, where Sanders has led preference polls for months. While Clinton’s campaign points out that he’s from neighboring Vermont, it’s Clinton and her husband, former President Bill Clinton, who have deep political roots in the state.

Clinton allies are more confident she’ll thrive when the race turns to states like South Carolina and Nevada, which have more black and Hispanic voters. But they’re deeply concerned about her struggles with young people, a key part of the coalition that propelled Barack Obama to the White House.

More than 8 in 10 Iowa caucus-goers under the age of 30 came to support Sanders, as did nearly 6 in 10 of those between 30 and 44, according to a survey conducted for The Associated Press and the television networks by Edison Research.

“That’s unprecedented,” said Paul Begala, a longtime Clinton ally who advises a super political action committee backing her candidacy. “She cannot be president without the enthusiastic support of those Sanders voters.”

Clinton conceded in an interview with CNN that she is “going to have some work to do to reach out to young voters.”

Sanders has resonated with his call for a “political revolution” to fix an economy he calls rigged for the wealthy.

Brad Anderson, an Iowa political consultant who supports Clinton, said Sanders’ supporters had a noticeably easier time conveying their message to undecided voters.

Campaigning in New Hampshire on Tuesday, Clinton largely stuck to the message she used during the last days in Iowa, casting herself as a liberal who can accomplish change — an implicit suggestion that Sanders’ proposals are unrealistic.

But her husband hinted a more aggressive approach toward Sanders may be coming.

“We should talk about what the honest differences are: first, on what they want to do and how they want to pay for it; and secondly, who’s the best to do it,” the former president said.

JULIE PACE, Associated Press
LISA LERER, Associated Press

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AP writers Catherine Lucey, Ken Thomas and Bill Barrow contributed to this report.

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