Romney takes day off trail as rivals troll South Carolina warning of frontrunner's ascendancy

Mitt Romney took the day off from the campaign trail Sunday, giving his rivals a chance to win over voters by contending Romney's record at a private equity firm and as governor of Massachusetts would hobble him as the Republican nominee against President Obama.

The contenders have less than a week to slow the front-runner's momentum before the crucial South Carolina primary, and a Monday night debate hosted from Myrtle Beach, S.C., hosted by Fox News, The Wall Street Journal and the South Carolina Republican Party could prove the last chance to make a convincing impression.

Watch the Fox News debate on Monday live at 9 p.m. ET.

Part of the challenge in gaining traction against Romney is the fractured Republican field. Former Pennsylvania Sen. Rick Santorum, Texas Gov. Rick Perry and Newt Gingrich are all vying for the social conservatives who don't want to support Romney, but who haven't coalesced around a single alternative.

Santorum, appearing on "Fox News Sunday," said he wasn't going to tell anyone to get in or out of the race, but the results of South Carolina will have a big impact on who survives through the nominating season.

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"There are a lot of the races and a lot of states to come. We need to get this eventually down to a conservative alternative to Mitt Romney. And those -- when we finally get matched up, and we believe it will be us," he said.

But that's the angle Gingrich is also pursuing.

"I think the only way that a Massachusetts moderate can get through South Carolina is if the vote is split," said Gingrich, who acknowledged that a Romney win in Saturday's primary would give the former Massachusetts governor an "enormous advantage" after back-to-back victories in New Hampshire and Iowa. Gingrich said he would "certainly have to reassess" his own candidacy if Romney prevailed.

The state's senior U.S. senator said a Romney victory probably would wrap up the nomination. "I think it should be over," said Sen. Lindsey Graham. "I'd hope the party would rally around him," he told NBC's "Meet the Press."

Romney took a rare day off from campaigning while his opponents focused on the South Carolina coast. They also attended church services and prayer breakfasts in a state with a large population of evangelicals and other conservative Christians.

No Republican has won the party's presidential nomination without carrying South Carolina, and polls show Romney leading in the state. And while the Palmetto State is often described as too evangelical and culturally southern for Romney, he is leading in virtually every poll.

Still, the state is known for campaign surprises, and there's still time for twists and turns. Undercurrents of anti-Romney sentiment could be stronger than they seem, especially after an influential group of social conservatives and evangelical leaders in Texas on Saturday endorsed Santorum.

"I think they did so because they know that I'm the consistent conservative," Santorum said. "I'm someone who's willing to stand up for all of the issues ... that are important to conservatives across in this country and they saw me as the one best chance of winning."

Santorum said Republicans would have a hard time beating Obama in the November election if Romney were the nominee. He cited Romney's push for mandatory health insurance coverage in Massachusetts.

"Romneycare (is) a real scarlet letter here," Santorum said. "We can't have a nominee that takes away the most important issue of this election, which is an explosion of federal government and robbing the people's freedom on the federal level with Obamacare. And Romneycare, which was the predecessor to Obamacare, just disqualifies him and his ability to go out and aggressively go after this top down approach to health care."

Gingrich and Perry also used television interviews to focus on Romney's former leadership of the Bain Capital private equity firm. Many Republican and conservative leaders have rebuked his rivals for criticizing Romney's role at Bain. But both Gingrich and Perry defended raising questions about Bain's business practices, saying Romney's tenure would come under relentless assault from Democrats in the general election.

Gingrich said questions about Bain were fair game since Romney has made his experience in the business world the chief selling point for his candidacy at a time when Obama is vulnerable due to high unemployment and the sluggish recovery from the Great Recession.

"It's fair to raise the questions now, get them out of the way now to make sure that whoever we nominate is clear enough, public enough, accountable enough that they can withstand the Obama onslaught," Gingrich said.

Gingrich also said he planned to release his tax returns this week and called on Romney, who has refused to do so, to follow suit.

"He'll never get through the fall without releasing his records," Gingrich said, insisting the country "deserves accountability and ... transparency."

Perry suggested Obama's team was eager to attack Romney over his Bain tenure. That was a point Obama campaign adviser David Axelrod confirmed.

"If this is a fatal flaw we need to be talking about it now, not talking about it in September and October," Perry said.

Axelrod portrayed a campaign against Romney as a debate over values and the needs of the middle class.

"Is that the economic vision for this country -- outsourcing, off-shoring, stripping down companies, lowering wages, lowering benefits? I don't think that's the future for this country," Axelrod told CNN.

While far back in the field after a third-place finish in New Hampshire, former Utah Gov. Jon Huntsman picked up the endorsement of The State, South Carolina's largest newspaper, which described him as a "realist" able to appeal to the centrist voters who will decide the general election.

The Associated Press contributed to this report.