CNN also projected that Texas Rep. Ron Paul will finish in second place and former Utah Gov. Jon Huntsman will finish third. Former House Speaker Newt Gingrich and former Pennsylvania Sen. Rick Santorum trailed, with Texas Gov. Rick Perry at the back of the pack.
The CNN projection, based on early results and exit poll data, came after final polls closed in the state at 8 p.m. ET.
Exit polls indicated Romney would get about 36% of the vote, with Paul receiving 23% and Huntsman 18%. Gingrich and Santorum came in with 10% and Perry with 1%, according to the exit polls.
While Romney’s victory was expected, based on polling in recent weeks, the battle for second place loomed as the most hotly contested result, with implications for the next primary in South Carolina on January 21.
A triumphant Romney told exuberant supporters they made history with a second straight victory after his narrow first-place finish last week in the Iowa caucuses.
“Tonight we celebrate. Tomorrow we go back to work,” Romney said, immediately assuming the posture of the Republican nominee who will face President Barack Obama in the November election.
Calling Obama “a failed president,” Romney said he was asking “the good people of South Carolina to join the good citizens of New Hampshire to make 2012 the year he (Obama) runs out of time.”
The crowd interrupted Romney with chants of his first name as he outlined a campaign strategy that portrayed Obama as a European-leaning big government advocate while defining his candidacy as a return to American ideals.
“This president puts his faith in government. We put our faith in the American people,” Romney said to cheers.
Paul told CNN that he expected to raise more money after a second-place finish, and he then told cheering supporters that their campaign for freedom in America would continue to grow.
Referring to Romney, Paul said “he certainly had a clear-cut victory, but we’re nibbling at his heels,” giving a chuckle as the crowd chanted “President Paul.”
In response to criticism by rivals that his calls for scrapping the Federal Reserve and bringing home American forces from around the world were dangerous, Paul declared: “We are dangerous, to the status quo.”
Huntsman told his supporters “I think we’re in the hunt,” adding “Hello, South Carolina” to emphasize his third-place finish would keep him in the race.
Earlier, Gingrich also said he would head to South Carolina on Tuesday night to being campaigning there, and Perry already was in the Palmetto State in what amounted to a concession of New Hampshire.
“Tonight’s results in New Hampshire show the race for ‘conservative alternative’ to Mitt Romney remains wide open,” Perry said in a statement. “… I believe being the only non-establishment outsider in the race, the proven fiscal and social conservative and proven job creator will win the day in South Carolina.”
A record 250,000 voters were expected to turn out for the GOP primary on an unseasonably warm winter day, Deputy Secretary of State David Scanlan told CNN. With no competitive challenger to President Barack Obama on the Democratic side, more “undeclared” voters could weigh in on the Republican race, he said.
“We’re hearing that the turnout is steady,” Scanlan said. “There aren’t lines that are backing up, but people are just constantly moving through the polling places. It’s certainly what we would expect during a presidential primary.”
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Romney, the former Massachusetts governor, earlier told Boston radio station WRKO that winning New Hampshire after Iowa would make history of a sort.
“It will be the first time I think anyone who is not an incumbent in our party would have won Iowa and New Hampshire,” Romney said.
Early exit poll data showed that nearly seven out of 10 Republican voters in the state were very worried about the economy and their personal financial situation.
One in four said the deficit was the most important issue. Also, more than three-quarters of respondents said the series of Republican debates was important to their final decision, while less than half said television ads were important.
The first votes were cast just after midnight in the tiny communities of Dixville Notch and Hart’s Location. In Dixville Notch, Romney and Huntsman, the former Utah governor and ambassador to China, led with with two votes each, while Romney edged Paul 5 to 4 in Hart’s Location.
Paul and Gingrich won one vote each in Dixville Notch. Huntsman placed third with two votes in Hart’s Location, while Gingrich and Perry got one vote each.
Obama received all the votes in the Democratic primary in both locations.
Huntsman, who skipped last week’s Iowa caucuses to campaign heavily in New Hampshire, told CNN his showing in Dixville Notch was “a harbinger of things to come.”
One of New Hampshire’s more than 300,000 “undeclared” or independent voter, Linda Underhill, told CNN on Tuesday that she decided to support Huntsman.
After initially backing Romney, Underhill shifted to Huntsman, calling him smart and likely to take a bipartisan approach.
“In the past few days, I watched him very closely,” Underhill said. “I just feel he is more genuine.”
Meanwhile, Gingrich argued that a Romney showing in the 30% range, as the most recent polling suggested, could hurt the front-runner even if he wins Tuesday’s contest.
“If he can’t come close to 50% here, it’s very unlikely he can sweep the nomination,” Gingrich told reporters in Bedford. “And I think that gives the party time to take a deep breath, look at his record and begin to realize that maybe this isn’t the right guy to run against Obama.”
Gingrich has been pounding at Romney since Iowa, complaining about a massive negative ad campaign against him by allies of the former Massachusetts governor. A Gingrich-allied super PAC has already launched its own anti-Romney barrage in South Carolina. And Gingrich and others have honed in on Romney’s years as a financier with Bain Capital, accusing him of getting rich by gutting companies and laying off workers.
Romney will have to answer questions about that in conservative South Carolina, Gingrich told CNN on Tuesday, acknowledging that the Palmetto State will be a key contest for his own presidential hopes.
“We’re going to go all out to win South Carolina. We think that’s a key state for us,” Gingrich said, describing the race there as a contrast between himself — a “Georgia Reagan conservative” — and Romney, “a Massachusetts moderate.”
Asked about the negative ads from the Gingrich camp, Romney told WRKO on Tuesday that they “will not help” his rival.
“All I have got to do is keep my head down, keep talking about my message of getting America back to work, my experience in having led two businesses successfully, the Olympics successfully,” Romney said.
Gingrich wasn’t alone in attacking Romney’s business record. In South Carolina, Perry told supporters Romney’s firm “looted” a photo company in Gaffney and a steel company in Georgetown.
“I would suggest they are just vultures,” Perry said. “They are vultures that are sitting out there on the tree limb waiting for the company to get sick, then they swoop in, they eat the carcass, they leave with that and they leave the skeleton.”
Romney got a mere eight more votes than Santorum in the Iowa caucuses, while Paul finished a strong third. The libertarian doctor and Congress member has touted his plan to downsize government and chided the frontrunners for being unwilling to push for the kind of overhaul he believes Washington needs.
Santorum, meanwhile, saw his New Hampshire poll numbers surge from single digits to the low double digits after his near-win in Iowa. However, was downplaying expectations for Tuesday night.
“We haven’t spent a penny on broadcast television here in New Hampshire. We’ve only spent five days campaigning here in the last month. We just came here starting at two or three points pretty much tied with Rick Perry in New Hampshire. We’ve been working hard and now into the double digits. Hopefully we can finish well,” Santorum said.
Romney tops most national polling and is ahead in the latest surveys in South Carolina and Florida, the next two states to hold contests following New Hampshire. But he took new criticism Monday after a speech to the Nashua Chamber of Commerce, when he said he wanted Americans who were unhappy with their health care coverage to be able to switch insurance companies.
“I like being able to fire people who provide services to me,” he said. “You know, if someone doesn’t give me the good service I need, I want to say, ‘You know, I’m going to go get someone else to provide that service to me.’ ”
The first seven words of that sentence — “I like being able to fire people,” dangled like low-hanging fruit, and some of Romney’s rivals pounced.
“Governor Romney enjoys firing people. I enjoy creating jobs,” Huntsman said at a campaign stop in Concord on Monday.
Romney Communications Director Gail Gitcho said opponents are taking Romney’s remarks out of context — a point on which Gingrich and Paul defended him Tuesday. But the attacks have fed the image of Romney that his GOP opponents and Democrats have pushed: That he’s a wealthy businessman who can’t connect to average Americans.
“The language was a little bit clumsy and open to misinterpretation and that might raise some questions about whether or not he’s the right person to debate Barack Obama, which I think is an essential characteristic for this fall, but nonetheless, I thought it was unfair to suggest that he actually liked firing people,” Gingrich said.