GREER, South Carolina (Reuters) - Prominent Republicans and business leaders rallied to Mitt Romney's defense on Thursday against charges of job killing from his rivals that threaten to undermine his central argument for why he should be elected president.
After rolling up campaign victories in Iowa and New Hampshire, Romney has come under fire in South Carolina from opponents Newt Gingrich and Rick Perry over his tenure at Bain Capital, a private equity firm that bought and restructured companies, sometimes resulting in job losses.
Romney was backed by a group that ranged from former New York Mayor Rudy Giuliani to conservative talk radio host Rush Limbaugh, and Tom Donohue, president of the U.S. Chamber of Commerce.
"What the hell are you doing, Newt?" Giuliani told Fox News. "I expect this from Saul Alinsky! This is what Saul Alinsky taught Barack Obama, and what you're saying is part of the reason we're in so much trouble right now," he said, referring to the late left-wing community organizer and writer.
Donohue said he was disappointed with the "intramural carrying-on within the Republican Party, attacking one of the candidates, Romney, who has an extraordinary business experience."
Gingrich fired back, describing as "baloney" the argument that criticizing Romney's business record was an attack on the free enterprise system.
Republicans are worried the attacks on Romney for overseeing job cuts in the 1990s hit at the party's pro-business ethos and help Democratic President Barack Obama's re-election campaign.
The accusations strike at the heart of Romney's case for why he should be elected next November to replace Obama: that America needs a business executive who can create jobs and get the U.S. economy going again.
Conservatives Gingrich and Perry want to make a stand in South Carolina and stop Romney's march toward the 2012 Republican presidential nomination. A South Carolina win would make Romney virtually unstoppable.
Romney defended himself at a news conference after a campaign event at a motorcycle dealership in South Carolina.
He said Bain helped start four companies: Staples, Bright Horizons Children's Centers, Sports Authority and Steel Dynamics that had created well over 100,000 jobs, far offsetting the "few thousand jobs" lost from failing enterprises elsewhere, he said.
Insisting some businesses have to be cut back to survive, Romney also tried to convince voters he is not a callous, profit-driven corporate raider as Gingrich and Perry claim.
"I think any time a job is lost it's a tragedy to the family. For the individual who loses the job, it's just devastating. And every time that we invested in a business it was to try to encourage that business to have ongoing life," he said.
Attacks on Romney from fellow Republicans were muted on Thursday but Gingrich defended himself.
"He ought to be willing to discuss the 25-year business record instead of suddenly jumping up and saying any question's a sign you're attacking free enterprise. That's baloney," Gingrich told Fox News.
A South Carolina donor for Perry, who called Bain "vultures" this week, defected to Romney because of the anti-business tone of the Texan governor's criticism, ABC News reported.
A pro-Gingrich group has unleashed a 27-minute video attacking Romney's Bain record.
Democrats like what they are hearing. They want to defeat Romney, should he become the nominee, by questioning his business record in what could be a difficult campaign year for Obama as he grapples with a sluggish economy.
"He wasn't focused on creating jobs at Bain," said Democratic National Committee Chair Debbie Wasserman-Schultz.
"He was focused on making money - nothing wrong with that but when you're making money by outsourcing jobs, stripping down companies and bankrupting them for profit, that's not the best of the free enterprise system."
South Carolina, a deeply conservative state, is notorious for dirty political tricks and figures to be no different this year.
Gingrich, seething from Romney attack ads that knocked him down to a fourth-place finish in Iowa and put his campaign in trouble, has brought up an old tale about Romney.
In a new ad, Gingrich reminds voters that Romney placed the family dog in a portable kennel and attached it to the roof of his station wagon to take his family on a long drive to Canada in the 1980s.
Since the story came to light in 2007, Romney has come under fire from animal rights activists and been the object of jokes in the media.
Editing by Peter Cooney