Rivals go south, frantic to block Romney trifecta

For all of Romney's challenges, the presence of a cluster of socially conservative candidates fighting to be his chief alternative could work in his favor by splitting the vote on the party's right flank. Santorum, Gingrich, Perry and others split the faith-focused vote in Iowa. South Carolina also has a large contingent of evangelical voters, some of whom remain suspicious of Romney.

Unlike New Hampshire, South Carolina could end up being the last stop for some candidates.

Perry, for one, has had back-to-back dismal showings, and is dismissing the earlier contests as inconsequential as he looks to right his struggling campaign in South Carolina.

"They kind of start separating the wheat from the chaff, if you will," Perry told a cafe crowd Tuesday. "But South Carolina picks presidents."

Gingrich, the former Georgia lawmaker, is also playing on his regional ties.

"The ideal South Carolina fight would be a Georgia conservative versus a Massachusetts moderate," he said, echoing a theme central to his fierce ads.

Santorum and Huntsman also have vowed to press on in the face of Romney's latest victory. Santorum wants to claim the conservative mantle; Huntsman eschews ideological labels and is selling himself as someone who can heal a polarized nation.

"Third place is a ticket to ride, ladies and gentleman," Huntsman boomed from the lectern after finishing third in New Hampshire. "Hello, South Carolina."

But Chip Felkel, a veteran GOP strategist in South Carolina who aided the campaigns of both Bush presidents, said before Tuesday's vote that a convincing Romney win would make him hard to stop. Felkel, who remains neutral, predicted voters on the fence will break Romney's way.

"The air of inevitability does kick in and a lot of those undecideds will want to go with the guy who's perceived to be the one to get the nomination," Felkel said.

Associated Press writers Shannon McCaffrey and Beth Fouhy contributed from New Hampshire.