Mitt Romney has begun a 10-day quest for victory in the South Carolina Republican presidential contest, where a win could all but ensure that he will be his party’s choice to run against President Barack Obama.

Romney has huge advantages coming into South Carolina. He won the first two nominating contests, has plenty of money to spend and has the backing of much of the party’s establishment, including the state’s governor. They see Romney as the candidate most likely to defeat Obama and want to avoid a long, potentially damaging nomination fight.

Romney’s opponents have been unable to coalesce behind a single rival in the six-man race. The candidates with presumably the best prospects in the conservative southern state – Rick Santorum, Newt Gingrich and Rick Perry – all fared poorly in Tuesday’s New Hampshire primary.

“I don’t want to be overconfident,” Romney said yesterday. But increasingly, he was talking about his plans for challenging Obama in November, not his primary foes of the moment.

Meanwhile, Obama made a quick visit to his Chicago headquarters to chart his re-election campaign, preparing for his Republican opponent and stocking up on campaign cash as he thanked hometown staffers.

“If you’re willing to work even harder in this election than you did in the last election, I promise you, change will come,” Obama said at a large fund-raising event at the University of Illinois at Chicago.

“You can’t back down – not now. We won’t give up – not now,” Obama said. “We’ve got to send a message we are going to keep pushing and fighting for the change that we believe in.”

A Romney victory in South Carolina on 21 January is not a sure thing.

Republicans are uncertain about whether Romney, former governor of the northern, liberal state of Massachusetts, is sufficiently conservative. It’s not clear if the state’s core evangelicals will rally behind a Mormon like Romney.

South Carolina is also known for tough political fights and this year isn’t likely to be an exception.

Wednesday’s events marked the unofficial start of a campaign that includes a pair of televised debates, millions of dollars in television ads and the first competition of the year in a state with high unemployment, a major military presence and a large population of evangelicals.

Gingrich, former speaker of the House of Representatives, has led the charge against Romney. He delivered a fresh attack on Romney’s business career and a new television ad painting him as a flip-flopper on abortion.

Texas Rep. Ron Paul, who ran second in New Hampshire, chastised Gingrich and Perry for criticising the front-runner’s experience as a venture capitalist whose firm acquired, slimmed down and then spun off existing companies, often earning large profits in the process.

Former Utah Gov. Jon Huntsman, who finished third in New Hampshire, also urged Republicans to ease the criticism over Romney’s business career and focus instead on his record as governor of Massachusetts.

“He didn’t deliver any big bold economic proposals,” Huntsman said. “I delivered the largest tax cut in the history of my state.”

Texas Gov. Rick Perry drawled his way through a busy campaign day, displaying a southern attribute that Romney, the former Massachusetts governor, could not hope to match.

Joblessness in South Carolina, at 9.9%, is much higher than in Iowa (5.7%) and New Hampshire (5.2%) combined. By some estimates, as much as 60% of the primary electorate here is comprised of evangelicals.

Culturally and historically, the state has relatively little in common with either Iowa or New Hampshire.

“South Carolina is going to be different,” said Santorum, a former Pennsylvania senator. “It is wide open for anyone.”