Huckabee, the former governor of Arkansas, told CBS' "Face the Nation" his campaign is "on fire" and said he's drawing crowds up to four times the size expected.

"These are folks who are ready to sign up and who are ready to walk through eight feet of snow to get to the polls," Huckabee said.

He took it as a badge of honor that fellow GOP contender Fred Thompson attacked him recently.

"It's a real form of flattery when you start getting attacked, because no hunter points his gun at a dead carcass," he said.

Paul, a libertarian GOP congressman from the Houston area, said the $5 million in contributions his campaign pulled in last week shows Americans "are just starved for" his vision of limited federal government. Still, he recognizes he's a long-shot.

"But compared to 12 months ago, I would say that it's much more likely now," Paul said. "... Don't try and tell my supporters that there's not a chance, because they believe."