Analysts said South Carolina may be the last, best chance for other /*GOP*/ candidates to stop /*Mitt Romney*/'s momentum.
Each of the candidates, with the exception of /*Ron Paul*/, planned to meet at a forum in Charleston on Saturday.
Meanwhile in Texas, more than 150 conservative Christian leaders voted to support /*Rick Santorum*/.
Many conservatives think Romney is too moderate. However the dynamics that lifted Romney to wins in Iowa and New Hampshire seem to be working for him in South Carolina, a state often described as too evangelical and culturally southern for his background.
But on the surface, at least, Romney is well-positioned with a week to go. If he wins South Carolina, only a seismic change in the campaign will keep him from becoming the nominee.
The next primary, on Jan. 31, is in Florida, a sprawling and expensive state where Romney's superior money and organization could essentially put the matter to rest, kicking off the general election against /*President Barack Obama*/.
The Associated Press contributed to this story.
