Bernie Sanders' stunning popularity is 'almost unheard of'

New Hampshire Democrats really like Sen. Bernie Sanders (I-Vermont).

A new CNN/WMUR poll released on Tuesday found the insurgent Democratic presidential candidate beating rival Hillary Clinton by a 27-point margin among primary voters in New Hampshire.

The same poll showed that 91% of those voters hold a favorable opinion of him, compared to the 65% that hold a favorable view of Clinton.

"Sanders' net favorability rating is an almost unheard of +84%," wrote pollsters at the University of New Hampshire, which conducted the survey. Clinton's net-favorability rating is a positive 39%.

While Sanders widens his lead in New Hampshire, which holds the first primary contest, the first-caucus state of Iowa is a much different story, where the race is a virtual dead heat.

The most recent Bloomberg Politics/Des Moines Register poll released this month found the two candidates' favorability ratings at almost identical highs, with 89% of likely Democratic caucus-goers viewing Sanders favorably and 86% saying the a favorable view of Sanders, and 86% saying that they have a favorable view of Clinton.

Much of Clinton's eventual support in both early-nominating states will rely on whether she can mobilize female supporters and close the gap among male voters.

In both Iowa and New Hampshire, recent polls have found Clinton trailing among male voters by significant margins. The latest CNN/WMUR poll found that 70% of likely male voters in New Hampshire currently support Sanders, whereas only 26% support Clinton. A recent Quinnipiac University poll of Iowa voters found that of the men who plan to caucus in Iowa, 61% currently back Sanders, compared to 30% who back Clinton.

In Iowa and New Hampshire, where white voters dominate the likely-voter pool, the former secretary of state still appears to be running strongest among women, voters over the age of 50, and those who came out to vote in the 2008 and 2012 primaries.

Privately, some Democrats have begun to acknowledge that Sanders could win both states. But they point out that he has an uphill climb in the next several nominating contests.

"The Clinton people are now facing the prospect where they could lose the first two states," a Democratic party strategist unaffiliated with any of the presidential campaigns told Business Insider last week.

The strategist noted that Sanders will need to make big gains among minority voters in South Carolina and Nevada, far more demographically diverse states than Iowa and New Hampshire.

"The good thing for her, and the bad thing for Sanders, is that because he spent so money and put so much stock in [Iowa and New Hampshire], I don't see where it gets better for him," the strategist said. "I don't see him winning Nevada. You look at that electorate and the amount of Latinos that represent the Democratic Party in Nevada. I don't see him making inroads there."