Mitt Romney holds a wide lead in polls in the state.
The other candidates will use Saturday night's debate to position themselves for the New Hampshire primary on Tuesday and for a key primary two weeks from now in South Carolina.
Candidate Rick Santorum is in hurry-up mode. After the debates, he'll head to South Carolina far in advance of the first southern primary on Jan. 21.
"We felt it be a good chance to make a splash in South Carolina, we're coming back that night and we're going to be here Monday and Tuesday and we're gonna run it through the finish line," Santorum said.
Former Massachusetts Gov. Mitt Romney, who owns a house in New Hampshire, campaigned in South Carolina two days ago. Now touring the Granite State with Romney is South Carolina Gov. Nikki Haley.
"You take care of him in New Hampshire, I'll take care of him in South Carolina," Haley said.
Candidates Santorum, former house speaker Newt Gingrich and Texas Gov. Rick Perry expect higher vote percentages in South Carolina, where Republican voters are counted among the most socially conservative in country. In Manchester, New Hampshire voters we talked to understood the southern obsession.
"If you're looking to win the presidency, obviously South Carolina is a very important state right now," said New Hampshire voter Phil Gagnon.
Among the candidates who have not made a South Carolina trip since Iowa are Texas Congressman Ron Paul, Gingrich, and former Utah Gov. Jon Huntsman. Huntsman, who did not campaign in Iowa, is "all in" in New Hampshire:
"You've got to move a state," Huntsman said. " We've got to move New Hampshire to make South Carolina relevant. That's why we're putting in all this work is so important."