Republican candidates are racing against time to win over voters in South Carolina before its primary Saturday, where the result is predicted to either boost or break several campaigns.

The pressure to win is especially high because every victor in the state's primary has eventually become the Republican presidential nominee since 1980. Moreover, with different winners in each of the three major contests, a win in South Carolina is a must for the current frontrunners as well as for those struggling to stay in the race.

"There's no question we've got to do very well here," said the former Tennessee senator, Fred Thompson, who has yet to win a state, according to The Associated Press. "Different people are winning these different major contests and I think a different person will win Saturday in South Carolina. No one has settled in on anyone."

Political pundits have predicted that Thompson's campaign will call it quits if he fails to win South Carolina. With his campaign essentially on the line, the former "Law & Order" star has gone on an aggressive bus tour across the Palmetto state to rally support.

White evangelicals, who make up more than half of the expected primary voters, will be a huge deciding factor on Saturday. Republican candidates, as a result, have aggressively wooed this voting bloc with timely reminders of their pro-life record, opposition to gay "marriage", and strong commitment to Christianity.

Earlier last summer, Thompson had been a favorite among evangelicals who considered him a better alternative to pro-abortion, pro-gay rights than Rudy Giuliani. However, Mike Huckabee, an ordained Southern Baptist preacher, is now considered the favourite among born-again and evangelical voters.

Currently, Thompson and Huckabee are in a heated competition to win evangelical voters in South Carolina. Huckabee, a former preacher, is expected to rally pastors to help get their congregants out to polling stations to vote for him.

Meanwhile, Michigan winner Mitt Romney only hopes to stay competitive in South Carolina rather than pick up a first place finish. Although Romney invested much time and effort in South Carolina, many Christians still remain suspicious of his Mormon faith. The former Massachusetts governor will pursue the strategy to campaign in both South Carolina and Nevada.

New Hampshire winner John McCain is campaigning hard in hopes of claiming victory in the state he lost to President George W Bush in 2000. It remains to be seen if voters there have forgotten and forgiven his comment in 2000 describing a couple of Christian right leaders as being "agents of intolerance".

"For a minute there in New Hampshire, I thought this campaign might be getting easier," McCain said, according to AP. "But you know what? We've gotten pretty good at doing things the hard way, too. I think we've shown them we don't mind a fight."

According to latest polls, McCain and Huckabee are the current frontrunners in South Carolina.