TILTON, N.H. - Mitt Romney served up plates of steaming spaghetti to voters last night as his campaign basked in new polls showing him sustaining his dominant position in the Granite State and jumping to a surprisingly large lead in South Carolina, where the second GOP primary will be held in two weeks.
But as Romney’s rivals prepared to focus their fire on him in critical back-to-back debates - the first of them tonight - the political phenomenon of the day was former Pennsylvania senator Rick Santorum, who stunned the field by running almost even with Romney in last week’s Iowa caucus and drew such large crowds at a series of events yesterday that fire marshals had to intervene several times.
In Manchester, marshals forced the candidate and his supporters to move a meeting from an overcrowded restaurant to its parking lot.
For Santorum, Jon Huntsman, Newt Gingrich, and Ron Paul, their best opportunity to take Romney down a notch - or position themselves as the alternative to him - could come in what are shaping up to be the most important debates so far in a campaign season chock full of them.
Romney will undoubtedly be in the crosshairs, said Andrew Smith, a political science professor at the University of New Hampshire.
“Everybody’s going to have to beat up on Romney a little bit,’’ Smith said.
The candidates’ potential angles of attack have been surfacing over the past few days. Huntsman, who has focused exclusively on New Hampshire and desperately needs to do well to sustain his campaign, belittled Romney yesterday for saying, on several occasions, that “corporations are people.’’
“Of course corporations are not people,’’ Huntsman said. “Who would say such an outlandish thing? I can’t imagine anyone running for president would say something like that.’’
Romney, who made millions of dollars as a venture capitalist, has said he means by the comment that defending the interests of corporations means defending the well-being of those who work for them and own stock in them.
Yet Romney’s rivals could pay a price if they go too negative on the front-runner, Smith said. They could give Romney the chance to look good by staying above the fray.
“Romney can be the statesman in the group, who doesn’t have to go negative,’’ he said.
Tonight’s debate will be the first since an impressive surge in the polls for Santorum.
Voters who packed his events yesterday heard him spell out his strong conservative views on social and economic issues. At an event in Keene, for example, Santorum called for immediate cuts to Social Security benefits, even for current beneficiaries. The federal deficit is so immense, Santorum said, that everyone must sacrifice.
In addition to raising the eligibility age for Social Security, Santorum calls for tighter restrictions on benefits for the wealthy.
His position is more aggressive than those of other GOP candidates, who either refrain from talking about Social Security cuts or call for trims for future recipients.
Santorum also faced a number of questions on his positions on social issues.
“I’m sure you are sick of this question,’’ said one voter in Dublin, who then asked Santorum to explain again his position on gay marriage.
Santorum, becoming more impassioned each time the question was posed, said it was harmful to families because it could mean that children grow up without both a mother and a father.
“You’re robbing children of something they need, they deserve, they have a right to,’’ Santorum said. “They have a right to know and be loved by their dad and their mom. And that’s what marriage is about. It’s not about two people loving each other. There’s lots of people who love each other that we don’t give a privilege to and call it marriage.’’
During the hourlong visit to a school in Dublin, Santorum was asked about gay marriage three times and abortion once.
His conservative stances in a state that tends to be more moderate on social issues are likely to also be a topic in the debates. With Romney so far in the lead, the other candidates are jockeying for second place and the right to promote themselves as the alternative to Romney, said Dante Scala, associate professor of political science at the University of New Hampshire.
Santorum, Scala said, will be seeking to convince voters that he is electable. He and Romney will be positioned at the center of the candidates in tonight’s debate.
“I would imagine that he would be on center stage in ways he hasn’t been in previous debates,’’ said Scala.
“Santorum was the guy standing on the side, saying, ‘Look at me, look at me,’ ’’ Scala said, referring to previous debates. “Now people are looking, and there’s going to be some pressure that goes along with that.’’
Gingrich surged in the polls over the fall because of well-received performances in previous debates, but even another solid performance, Scala said, might do little to lift the former House speaker’s stock among New Hampshire voters, who will likely stick with Romney or be looking for a fresher face such as Santorum.
The two-hour debate tonight, sponsored by ABC News, Yahoo! News, and WMUR-TV, starts at 9. The debate tomorrow morning at 9 a.m. is hosted by NBC’s “Meet the Press.’’
Paul, who is second in most polls in New Hampshire, returned to the state yesterday and met with supporters at an airport hangar at Nashua Airport.
Romney spent the morning in South Carolina, a state where social conservatives, evangelical Christians, and military families have posed difficulties for the former Massachusetts governor in the past.
Tea Party activists and social conservatives are also girding for a major battle in South Carolina, potentially making the state a last stand against Romney if he is able to pull off the historic feat of winning competitive races in both Iowa and New Hampshire.
“He’s going to win in New Hampshire,’’ Senator John McCain told several hundred voters at a rally with Romney and Governor Nikki Haley in Myrtle Beach. “It’s going to come down, my friends, as it always does, to South Carolina. . . . If Mitt Romney wins here, he will be the next president of the United States. South Carolina, it’s up to you.’’
A CNN/Time/ORC poll released yesterday showed Romney with 37 percent of the vote, followed by Santorum with 19 percent, Gingrich with 18 percent, Paul with 12 percent, Perry with 5 percent, and Huntsman with 1 percent.
Both Romney and Santorum showed huge jumps from the previous CNN poll, conducted in early December, when Romney was at 20 percent and Santorum at just 4 percent. Their rise came at the expense of Gingrich, whose support dropped from 43 percent.
The poll found that 44 percent of voters had definitely made up their minds, while 49 percent said they could still change their decision. The poll of 485 likely Republican primary voters was conducted by ORC International on Jan. 4-5 and has a margin of error of 4.5 percent.
Romney was also ahead in the latest Suffolk University poll in New Hampshire, taking 40 percent of the expected voters, with Paul at 17 percent and Santorum at 11 percent.
At his lone event in New Hampshire, Romney cautioned his supporters not to become overconfident.
“Those polls,’’ he said, “they can just disappear overnight.’’
Michael Levenson and Brian Mooney of the Globe staff and Globe correspondent Shira Schoenberg contributed to this report. Material from the Associated Press was also used. Matt Viser can be reached at firstname.lastname@example.org.