CONCORD, N.H. (AP) -- 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. Ron Paul finished second, with Utah Gov. Jon Huntsman, Newt Gingrich and Rick Santorum trailing.
"Tonight we made history," Romney told cheering supporters.
With his victory, Romney became the first Republican to sweep the first two contests in competitive races since Iowa gained the lead-off spot in presidential campaigns in 1976.
Returns from the first 21 percent of New Hampshire precincts showed Romney with 35 percent of the vote, followed by Paul with 25 percent, Huntsman 17 percent and former House Speaker Gingrich and former Pennsylvania Sen. Santorum with 10 percent each.
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.
"Tonight we celebrate," Romney told his supporters. "Tomorrow we go back to work."
Candidates and political action committees aligned with them were reserving enormous amounts of television time for the first-in-the-South primary in little more than a week.
Unlike Iowa and New Hampshire, where unemployment was well below the national average, joblessness is far higher in South Carolina. That creates a different political environment for Romney, campaigning as a former businessman who is knowledgeable about creating jobs, as well as the rivals who have been attacking him as a corporate raider.
Seeking to undercut Romney's victory, Gingrich and others sere suggesting 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 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. Romney won their support overwhelmingly.
He ran even with Huntsman among the one-quarter of the voters who cited experience as the most important factor in selecting a candidate to support.
Paul ran first among voters who cited moral character or true conservatism.
As was the case last week in the Iowa caucuses, the economy was the issue that mattered most to voters, 61 percent of those surveyed. Another 24 percent cited record federal deficits.
Romney carried the first group and split the second with Paul.
The survey results came from interviews conducted for The Associated Press and the television networks with 2,636 voters across the state. It had a margin of sampling error of plus or minus 3 percentage points.
New Hampshire 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.
Bill Gardner, the New Hampshire secretary of state, predicted about 250,000 ballots would be cast in the GOP race. If so, that would be slightly more than double the turnout last week in Iowa's caucuses.
The state has about 232,000 registered Republicans, 223,000 Democrats and 313,000 voters who are undeclared or independent.
In his first presidential run in 2008, Romney finished second in the state to McCain. This time, he campaigned with the Arizona senator's endorsement, as well as backing from Sen. Kelly Ayotte and numerous other members of the state's Republican establishment.
As in Iowa, the economy in New Hampshire is in better shape than in much of the country. Unemployment in November was 5.2 percent, far below the national average of 8.6 percent.
Even so, the economy became the central issue here. Romney committed a pair of unforced errors in the campaign's final 48 hours, and the other contenders sought to capitalize.
On Sunday, after a pair of weekend debates only 12 hours apart, the millionaire former businessman said he understood the fear of being laid off. "There were a couple of times when I was worried I was going to get pink-slipped," he said, although neither he nor his aides offered specifics.
And on Monday, in an appearance before the Nashua Chamber of Commerce, Romney was discussing health insurance coverage when he said, "I like being able to fire people who provide services to me. If someone doesn't give me the good service I need, I'm going to go get somebody else to provide that service to me."
Huntsman, a former Utah governor, saw an opening. "Gov. Romney enjoys firing people. I enjoy creating jobs," he said.
Perry, campaigning in South Carolina, said, "I have no doubt that Mitt Romney was worried about pink slips -- whether he'd have enough of them to hand out."
And Gingrich said Bain Capital, the venture capital firm Romney once headed, "apparently looted the companies, left people totally unemployed and walked off with millions of dollars."
Romney has made his business experience a cornerstone of his presidential campaign, saying that Bain on balance created 100,000 jobs, and as a result, he understands how to help boost employment.
He sought to shrug off the attacks, saying he had expected them from Obama in the fall, but Gingrich and others had decided to go first. "Things can always be taken out of context," he said.
Already the campaign was growing more heated in South Carolina.
A committee created to help Gingrich said it would spend $3.4 million to purchase television ads attacking Romney.
A group formed to help Romney -- which ran ads in Iowa that knocked Gingrich off-stride -- said it would be on the air as well.
Associated Press writers Philip Elliott, Shannon McCaffrey, Kasie Hunt, Beth Fouhy and Holly Ramer in New Hampshire, Brian Bakst in South Carolina and Connie Cass in Washington contributed to this report. Espo reported from Washington.