"I am the one person who has a realistic chance of defeating him here, and I hope every conservative will reach the conclusion that to vote for anybody but Gingrich is, in fact, to help Romney win the nomination and to help him win the primary in South Carolina," Gingrich said on NBC's "Meet the Press."
Gingrich said he's hopeful he'll still get the social conservative vote despite the conservative Christian leadership's endorsement of Rick Santorum at a meeting in Texas during the weekend.
"I think that report was very highly exaggerated. We basically split that group. I got a very good number of votes and I think as of noon today that Reverend Jim Garlow and Congressman J.C. Watts and others who were there are going to be talking, and I think they'll indicate that I have very strong support from Christian conservatives and social conservatives and that that support continues," Gingrich said.
Santorum, on "Fox News Sunday," said he's not going to tell his competitors to get out of the race, but the playing field will eventually dwindle down to just him and Romney.
"When we get matched up, if you look at the polls done in other states down the road, we match up very well and ahead of Governor Romney almost every one of those state polls," Santorum said. "So, I feel like once this field narrows, when we get it down to a two-person race, we have an excellent opportunity to win this race."
Texas Gov. Rick Perry said despite the blow of not getting the social conservative backing, he has confidence he can still win the nomination. He said in an interview on CNN's "State of the Union," he has no intention of backing out of the race, even if he places last in South Carolina.
"Medal of Honor recipient Gen. Jim Livingston and former Navy SEAL Mike Thornton, who is also a Medal of Honor recipient, said, 'Hey, listen, the folks of South Carolina, they want to you come; they want to have that former Air Force pilot and veteran and chief of Air Forces and Armies in Texas to be in South Carolina so we have a real option,'" he said.
Sen. Jim DeMint, R-S.C., said no matter who wins the nomination, he believes "Republicans are going to be very united."
DeMint said on CBS' "Face the Nation," he believes any candidate would run the nation better than President Barack Obama, but acknowledged there's a division of votes.
"It's not unusual when you have a number of good candidates, which I think we do, for people to be divided. What I hope is that our eventual nominee will recognize the strengths of the other candidates and take a lot of those ideas and incorporate it into a platform that will unite us, and I think they will," DeMint said.
Meanwhile, comedian Stephen Colbert said though he's only launching an exploratory committee to find out if there's interest in him running for president, he believes he could land on the primary ballot in his home state of South Carolina.
"They say I can't get on the ballot in South Carolina?" he said on ABC's "This Week." "They said you can't go to the moon. They said you can't put cheese inside a pizza crust, but NASA did it."
Matt Moore, executive director of the South Carolina Republican Party, said Colbert's chances of winning the primary are "non-existent."
"South Carolina state law does not allow write-in ballots in presidential primaries. There is no 'blank' space on voting machines to write-in a candidate" Moore said in a statement to ABC. "Stephen Colbert has about as much a chance at being elected president in South Carolina as he does of being elected pope. Zero. It didn't work four years ago, and it won't work now. The gag is worn out."