After the most eventful day of the campaign thus far, candidates meet for what should be an exciting debate in Charleston on Thursday night.


CHARLESTON, S.C. -- Thursday night's Republican debate comes on the heels of one of the most exciting days of the 2012 campaign. First it turned out Mitt Romney didn't really win the Iowa caucuses. Then word leaked that Rick Perry would finally pull the plug on his doomed campaign. And that was just before 9 a.m. Meanwhile, anticipation of the evening's broadcast of ABC's damning interview with Newt Gingrich's second ex-wife hung over the day's proceedings.

All that, and a debate too? Indeed. The four remaining candidates -- Romney, Gingrich, newly crowned Iowa victor Rick Santorum, and Ron Paul (remember him?) -- meet onstage at 8 p.m. Eastern for a debate co-sponsored by CNN and the Southern Republican Leadership Conference. A few things to watch for:

* All eyes on Newt. Gingrich's surge in South Carolina is real. It's now apparent in multiple public polls; Thursday afternoon, polling guru Nate Silver upgraded his chances of winning the state to 48 percent (to Romney's 52 percent). Gingrich is a good debater, but he hasn't always shone when he's been confronted with the more uncomfortable parts of his record. Recall how Michele Bachmann made him squirm by hammering home his don't-call-it-lobbying work for Freddie Mac, repeating over and over the words "government-sponsored enterprise." With three candidates onstage gunning for him and his ego puffed up to historically dangerous levels, Gingrich could soar -- or stumble.

* Rick Santorum, punching up. He finally won Iowa, two weeks late. But Santorum is a desperate man these days, fighting to avoid finishing last. Santorum relishes being on the attack and has nothing to lose. Expect to see him take out his frustrations on all of his rivals.

* How's Romney feeling now? The calmly complacent front-runner has suddenly been replaced by a candidate who's won nothing but a gimme in New Hampshire and faces the prospect of South Carolina slipping through his fingers. Romney tends to get irritable when his confidence is shaken. Does he let Gingrich get under his skin, or try to rise above?

* Remember Ron Paul? Paul left the campaign trail for Thursday's debt-limit vote, and there's an increasing sense that his campaign is operating in a parallel universe. But he still has the potential to do damage, as evidenced by this brutal ad.

Image: Reuters