Romney swept to a big win in New Hampshire, with significant strength among the Republican and conservative base, and a big advantage as the most electable GOP candidate.

According to preliminary network exit polls, New Hampshire voters focused heavily on the country’s still struggling economy. Fully six in 10 called the economy the top issue, and about seven in 10 expressed deep concern about its direction. Romney had a better than 2 to 1 edge over his closest rivals among economy voters.

The former Massachusetts governor’s strength in New Hampshire extended to the most conservative voters, a group that favored Rick Santorum in last week’s Iowa caucus. Among “very conservative” voters Romney won about a third of voters to roughly a quarter for Santorum.

For Romney, 2012 brought a big improvement among the party base, winning nearly half of self-identified Republicans, up significantly from four years ago. He’s up too among those who see themselves as “somewhat conservative” and moderate or liberal, making up for slippage among the most conservative voters.

Romney more than doubled his share of the “strong tea party” vote from last week’s Iowa caucuses, beating other candidates among this group. In Iowa, Santorum won strong tea party backers by double digits.

Romney wins more than half of those prioritizing leadership qualities, but only three in 10 among those who want to be in sync on the issues. He neutralized Santorum’s big advantage among born-again Christians in Iowa, more than doubling his level of support of 14 percent and edging out Santorum in this group. Among non-evangelicals, Romney won by double digits.

The battle for second place - Paul and Huntsman

With Romney locking up New Hampshire relatively early in the campaign, the battle for second place provided more drama.

Ron Paul pushed through for his second strong showing, finishing in a dramatically better place than in 2008 thanks to broad support from young voters and independents. Paul won nearly half voters under age 30, up from 18 percent support in 2008. The problem is that there are too few of them to push him higher overall.

A larger share of his support comes from independents voters, a group that increased its share of the electorate by about 10 percentage points over 2008. Paul more than doubled his support in this group.

But those independent voters were important for Jon Huntsman too, who staked his entire campaign on a strong New Hampshire result. Huntsman peeled off about a quarter of independents from Romney and Paul. But a path forward for Huntsman out of New Hampshire looks challenging.

The strong showing for Huntsman is based on support from groups that are unlikely to make him competitive in South Carolina and other states that limit participation in primaries to party registrants. Huntsman’s best groups in New Hampshire were those who “strongly oppose” the tea party political movement and those who are “satisfied” with the policies of the Obama administration. The former Utah governor wins just 5 percent among very conservative voters.

These are preliminary results from the Republican caucus poll of 2,636 voters as they entered 40 randomly selected polling places places in New Hampshire on Jan. 10, 2012. The poll was conducted by Edison Media Research for National Election Pool, The Washington Post and other media organizations. The results for typical characteristics have a margin of sampling error of plus or minus three percentage points.

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