Romney Opens 21-Point Lead in South Carolina: Reuters/Ipsos Poll

WASHINGTON (Reuters) - Republican presidential candidate Mitt Romney has opened a wide lead over his rivals in the South Carolina primary election race, trouncing Newt Gingrich and gaining momentum in his march toward the party's nomination, a Reuters/Ipsos poll shows.

Romney, a former Massachusetts governor, could all but quash his rivals' presidential aspirations with a victory in South Carolina on Jan. 21 after winning the first state-by-state nominating contests in Iowa and New Hampshire.

Voters in South Carolina -- who have favored Republicans in nine of the last 10 presidential elections -- appear to have shrugged off attacks on Romney by rivals who accuse him of killing jobs as a private equity executive for Bain Capital in the 1990s.

The poll showed 37 percent of South Carolina Republican voters back Romney. Congressman Ron Paul and former Senator Rick Santorum tied for second place with 16 percent support.

Gingrich, a former speaker of the House of Representatives, has fallen far back after holding a strong lead in South Carolina in December. He was in fourth place at 12 percent in the Reuters/Ipsos poll.

In primary races things can change quickly but it does look like Romney is in position to win South Carolina, and if he wins ... that's sort of the end of the road for most of his challengers, Ipsos pollster Chris Jackson said.

MITT VS NEWT FEUD

Romney is clearly winning a feud with Gingrich that began in December before the Iowa caucuses and has become the most bitter fight in the selection of a Republican challenger to Democratic President Barack Obama in November's general election.

In a question asked of Republicans and Democrats, the poll found South Carolina voters would favor Romney over Obama by 46 percent to 40 percent.

Asked who they would choose if the nomination contest were solely between Romney and Gingrich, 62 percent of Republicans picked Romney and 30 percent went for Gingrich.

Senior Republican figures and business executives have berated Gingrich for painting multi-millionaire Romney as a ruthless corporate raider. Many Republican voters are also turned off by the attacks, highlighted in a video documentary produced by a funding group that backs Gingrich.

I think those attacks are misguided. The process of any economy has long been one of creative destruction. Some things grow and some things disappear, said Steve Matthews, a lawyer from Columbia, S.C., who plans to vote for Romney.

Romney argues that many more jobs were created by Bain than were lost in his time there.

Santorum, who surged into second place in the Iowa caucuses before fading in New Hampshire, got a boost on Saturday when Christian conservative leaders meeting in Texas endorsed him.

After Gingrich, Texas Governor Rick Perry placed next in the Reuters/Ipsos poll, with 6 percent support. Former Utah Governor Jon Huntsman, who was third in the New Hampshire primary, came in the lowest in the South Carolina poll with 3 percent support.

Even if Romney loses South Carolina by a point or two, he's got the organization, he's got the financial backing to do the long battle of attrition that other challengers really don't, said Jackson of Ipsos.

Romney's campaign announced this week it raised $24 million in the last three months of 2011, while Paul raised $13 million and Gingrich raised $9 million. Obama is way ahead of the Republicans in fundraising.

The Reuters/Ipsos poll was conducted online from Jan.10-13 with a sample of 995 South Carolina registered voters. It included 398 Republicans and 380 Democrats.

Statistical margins of error are not applicable to online surveys but this poll has a credibility interval of plus or minus 5 percentage points for Republicans and 3.4 percentage points for all voters.

(Additional reporting by Andy Sullivan in South Carolina, Editing by Alistair Bell and John O'Callaghan)