Republican U.S. presidential candidate Newt Gingrich scrapped his way to victory in South Carolina on Saturday as voters in the conservative state rejected frontrunner Mitt Romney's pitch that he is the best bet to fix a broken economy and defeat Democratic President Barack Obama.

Gingrich's come-from-behind win upended a Republican nominating race that until this week appeared to be a coronation for Romney, the former Massachusetts governor and private-equity firm chief.

Riding a series of feisty debate performances, Gingrich captured the lingering unease of conservative voters who view Romney's moderate past and shifting policy stances with suspicion. Gingrich, the former speaker of the U.S. House of Representatives, argued that he would be able to better articulate the party's conservative ideals in the November 6 election.

Gingrich's victory means that three different candidates have won the first three contests in the state-by-state battle for the Republican presidential nomination to face Obama, a Democrat, on November 6. Rick Santorum won the Iowa caucuses on January 3 and Romney won the New Hampshire primary on January 10.

U.S. television networks declared Gingrich the winner shortly after polls closed at 7 p.m. EST (0000 GMT).

Thank you South Carolina! Help me deliver the knockout punch in Florida, Gingrich wrote in a Twitter message.

Florida's January 31 vote is the next up in the state-by-state nominating contest.

South Carolina has been a tough state for Romney's presidential ambitions. In his previous run for the White House in 2008, Romney finished a poor fourth, with just 15 percent of the vote, behind winner and eventual Republican nominee John McCain. McCain endorsed Romney in the current campaign.

The race in the conservative southern state, known for gloves-off politics, has been upended in recent days as the two candidates have tried to portray each other as untrustworthy.

Gingrich attacked Romney's business record and reluctance to release personal tax information, while Romney pointed to Gingrich's past ethics lapses and alluded to his messy personal life.

Voters said they were overwhelmingly focused on fixing the sluggish economy and finding the strongest candidate to defeat Obama. Some 78 percent said they were very worried about the economy and 45 percent said that the most important trait in a candidate was the ability to beat Obama, according to exit polls released by CNN.


Those issues are the twin pillars of Romney's candidacy.

Romney had developed an aura of inevitability after strong showings in the first two nominating contests, and he led South Carolina polls by 10 percentage points a week ago.

Romney suffered a setback on Thursday when Iowa officials declared in a recount that he had come in second place in that state's January 3 contest, behind Santorum, instead of winning narrowly, as initially announced.

The thrice-married Gingrich has fended off publicity about his turbulent marital history and painted himself as the more conservative candidate with experience as a reformer. On Thursday, he rejected his second wife's accusation that he had asked her for an open marriage while he was having an affair with another woman in the 1990s.

He's a bulldog, and I'm tired of the namby-pambiness, said

Caron McBreairty, 53, who voted for Gingrich. I went with the good debater.

Kim Woods, 53, a photographer, said Gingrich's Washington experience - which Romney has belittled - was an asset. He's been in D.C. He's been in the political realm. He can get some things done, she said.

Romney has attacked Gingrich's ties to mortgage giant Freddie Mac and criticized his time in the nation's capital. His campaign has also highlighted Gingrich's $300,000 (192,604.01 pounds) fine due to ethics lapses while serving as House speaker 15 years ago.

Obama, who does not face a primary challenger, will have his turn in the spotlight on Tuesday with his State of the Union address. In a message sent to supporters on Saturday, he signalled the speech would include a partisan call for a return to American values of economic fairness.

Fueled by a grudge that has become almost personal, Gingrich has sown seeds of doubt among Republicans who were beginning to see Romney as the inevitable nominee to face Obama after his strong showings in Iowa and New Hampshire.

Romney has stumbled, acknowledging in the last week he pays a much lower tax rate than many Americans and struggling to answer questions about a planned release of tax records. Romney is among the richest men ever to run for the U.S. presidency and his stewardship of the private equity firm Bain Capital has been criticized by Gingrich and others.

Animosity between the two has been festering since December, when a group supporting Romney launched a blitz of negative TV ads in Iowa that effectively ruined Gingrich's campaign there.

The winner of South Carolina's Republican presidential primary has gone on to win the party's nomination in every presidential election since 1980.