CONCORD, N.H. — Former Massachusetts Gov. Mitt Romney won the New Hampshire primary Tuesday night, adding to a first-place finish in last week’s Iowa caucuses and establishing himself as the man to beat for the Republican presidential nomination.

Texas Rep. Ron Paul led former Utah Gov. Jon Huntsman for second place, with Newt Gingrich and Rick Santorum trailing.

Returns from the first 13 percent of the state’s precincts showed Romney with 36 percent of the vote, followed by Paul with 24 percent and Huntsman with 18 percent.

Former House Speaker Gingrich and former Pennsylvania Sen. Santorum had 10 percent and 9 percent respectively.

Romney battled not only his rivals but also high expectations as the ballots were counted, particularly since his pursuers had virtually conceded New Hampshire and were already pointing to the South Carolina primary on Jan. 21 as the place to block his rise.

Seeking to undercut Romney’s victory, Gingrich and others suggested that anything below 40 percent or so would indicate weakness by the nomination front-runner.

They didn’t mention that Sen. John McCain’s winning percentage in the 2008 primary was 37 percent.

Huntsman, in particular, staked his candidacy on a strong showing in New Hampshire. Santorum said second place “would be a dream come true.”

Not for Romney, the former Massachusetts governor, who swept into the state nearly a week ago after winning the Iowa caucuses by eight votes over Santorum. That result, coupled with New Hampshire’s proximity to Massachusetts, caused Texas Gov. Rick Perry to take a pass on the state, and the other contenders also all but conceded a Romney victory on Tuesday.

About one-third of Republican voters interviewed as they left their polling places said the most important factor in choosing a candidate was finding someone who could defeat President Barack Obama in the fall — a claim that Romney made often.

About one-quarter of those interviewed cited strong moral character or experience as the most important factor in selecting someone to support, followed by a candidate’s true conservatism.

As was the case last week in the Iowa caucuses, the economy was the issue that mattered most.

In tiny Dixville Notch, the village that traditionally votes at midnight. Romney and Huntsman each received two of the six votes. One went to Gingrich and the other to Paul. Huntsman said hopefully, “Dixville Notch might be a harbinger in this race.”

A Romney victory would make him the first Republican to sweep the first two contests in a competitive race since Iowa gained the lead-off spot in presidential campaigns in 1976.

Yet independents are permitted to vote in either party’s primary in New Hampshire, and the state has a rich history of humbling favorites, front-runners and even an occasional incumbent.

The state’s Republican voters embarrassed President George H.W. Bush in 1992, when he won but was held to 53 percent of the vote against Pat Buchanan, running as an insurgent in difficult economic times. Buchanan, who never held public office, won the primary four years later over Sen. Bob Dole of Kansas, who was the nominee in the fall.

In 2000, national front-runner George W. Bush rolled into the state after a convincing first-place finish in Iowa but wound up a distant second behind Sen. John McCain. Bush later won the GOP nomination and then the presidency.

Twelve Republican National Convention delegates were at stake on Tuesday, out of 1,144 needed to win the nomination. Obama was unopposed in the Democratic primary.