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Winners:

Santorum: This was his strongest performance of the entire campaign. He was confident, polished and substantive. He was determined to fight Newt Gingrich for the mantle of the "conservative alternative" to Mitt Romney. Does this give him enough of a boost to win South Carolina primary? Probably not. But, it does offer him the opportunity to pull in some of the undecided conservative voters and, ultimately, to deny Gingrich a "W" here on Saturday.

Gingrich: The former Speaker dominated the first five minutes of the debate with his scathing attack on moderator John King. King opened the debate by asking Gingrich to respond to allegations made by Gingrich's ex-wife Marianne in an interview with ABC News and the Washington Post that Gingrich encouraged her to enter into an open marriage. The question was an invitation for Gingrich to do what he does best - chastise the media. Gingrich got the crowd on their feet with lines like this one: "I'm am appalled that you would begin a presidential debate on a topic like that."

Meh:

Romney: After a halting performance in the Myrtle Beach earlier this week, Romney was more confident and poised. But, his halting answer on releasing his tax records elicited audible boos from the audience. Given the fact that this issue has dominated the race for the last week, it is surprising that he has yet to come up with a solid answer on this. Moreover, he continues to look uncomfortable when he tries to downplay his considerable wealth. But, the fact that Gingrich and Santorum both turned in solid performances tonight means there's still a strong likelihood that they divide the conservative vote and allow Romney to squeak out a win.

Losers:

Mainstream Media: There is no fatter and more appealing target to an audience of conservative Republicans than the mainstream media. And, John King opened the floodgates tonight with his opening question to Gingrich about accusations from his ex-wife. The question only helped to sow the seeds of distrust among conservatives about the intentions of traditional media organizations.

Ron Paul: Even though there were only four candidates on the stage tonight, Paul faded into the background. Even Santorum and Gingrich, who have enjoyed sparring with the Texas Congressman in previous debates, essentially left him alone tonight - a sign that his relevance in this state is much more limited.

Foreign Policy: Iran - and its threat of close the Straits of Hormuz - has been a big talking point on the campaign trail and in Washington. Still, we didn't hear about Iran - or any other foreign policy issue of any sort tonight.