President Obama "has run out of ideas - now he is running out of excuses," Romney told chanting supporters about a half-hour after the polls closed, sounding as if he were delivering a convention acceptance speech - along with a plea to Republicans in the next primary. "And tonight, we are asking the good people of South Carolina to join the citizens of New Hampshire and make 2012 the year he runs out of time."
Former Pennsylvania Sen. Rick Santorum and former House Speaker Newt Gingrich were battling for fourth place with more than half the vote counted. Both were looking ahead to next week's South Carolina contest, with a more conservative electorate and a fresh chance to try to consolidate religious conservatives behind them as the main alternative to Romney.
Santorum told supporters late Tuesday that his immigrant Italian grandfather "was not deterred by temporary setbacks.. . . We are going to go on to South Carolina."
Texas Gov. Rick Perry trailed far behind.
In the days leading up to the New Hampshire primary, rivals stepped up attacks on Romney's record as onetime chief executive of the investment bank Bain Capital, accusing him of destroying communities by laying off thousands of workers from the companies the firm purchased and flipped or reorganized.
"Is capitalism really about the ability of a handful of rich people to manipulate the lives of thousands of other people and walk off with the money?" Gingrich said earlier Tuesday.
Gingrich and Perry, who pulled out of New Hampshire to stump in South Carolina, led the charge. The attacks echoed a critique that Obama and Democrats have been making of Romney as a heartless corporate raider who does not relate to average Americans.
A super PAC supporting Gingrich, called Winning Our Future, has bought a 27-minute documentary about Bain-caused layoffs, and says it has reserved $3.4 million in TV time to attack Romney on the issue in South Carolina.
Romney did not help his cause in the last two days, when the multimillionare first said he understood what it was like to fear a "pink slip," and then told a business audience that he liked "being able to fire people." The last was a reference to the importance of consumer choice among health insurance companies.
"President Obama wants to put free enterprise on trial," Romney told supporters Tuesday night in declaring victory. "In the last few days, we have seen some desperate Republicans join forces with him. This is such a mistake for our party and for our nation. This country already has a leader who divides us with the bitter politics of envy; we must offer an alternative vision."
Paul said Tuesday night that he had called Romney to congratulate him, but added, "We are nipping at his heels." He told his supporters they had won "a victory for the cause of liberty tonight" and embraced the description of his movement by establishment Republicans and some media commentators as dangerous.
"They're right - we are dangerous to the status quo in this country," Paul, 76, said.
Huntsman declared to his supporters, "Third place is a ticket to ride.. . . We're in the hunt." He told CNN earlier that he was continuing on to South Carolina.
To a certain extent, Romney was playing on his home field. He owns a sprawling vacation home on Lake Winnipesaukee, and, more importantly, led neighboring Massachusetts from 2003 to 2007. Many residents of the southern part of New Hampshire, the state's most populous, commute to Boston and get their news from the city's television stations. That proximity has benefited Massachusetts politicians of both parties in presidential primaries here.
Santorum, who came within eight votes of beating Romney in Iowa by appealing to social conservative voters in a relentless shoe-leather campaign, found the going a little rougher in New Hampshire, a state with a traditional of fiscal conservatism combined with a "live and let live" approach to personal freedom.
At several town hall meetings, hecklers pressed him on his opposition to same-sex marriage, for instance.
Luke Breen, 52, a financial analyst voting in Londonderry, said he would not support Santorum, saying the former senator seemed intolerant. He backed Huntsman.
"He seemed to be more worldly," Breen said. "I know gay people and everyone has to have rights under our constitution."
Contact politics writer Thomas Fitzgerald at 215-854-2718, tfitzgerald@phillynews.com, or @tomfitzgerald on Twitter. Read his blog, "The Big Tent," at www.philly.com/BigTent.