OK, folks, here we go. With Gingrich and Romney even in South Carolina, according to some polls,  this is going to be a hugely consequential debate.
Romney hits early, talking about what a family man he is — knowing that the Marianne Gingrich bombshell is going to fall later tonight. Newt reminds the South Carolina crowd that he is a fellow Southerner.
UPDATE: Newt on the open marriage. He’s making this about the news media. “I am appalled that you would begin a presidential debate on a topic like that,” he growls at John King. Standing ovation from the partisan audience.
Gingrich says asking this question “is as close to despicable as anything I can imagine.” Really? Closer to despicable than asking your first wife for a divorce while she was in her hospital bed, as Gingrich did so he could marry his mistress Marianne?
“I am tired of the elite media protecting Barack Obama by attacking Republicans,” he said. The Limbaugh line. Brilliant — but, well, despicable.
UPDATE.2: I’ve just seen that the Gingrich divorce story isn’t wholly true . The divorce was in the works before his hospital visit. It’s not clear what he said in the hospital.
UPDATE.3: I don’t understand why Romney is continuing to go after Barack Obama. If he hopes to face Obama down this fall, he’s got to get through Gingrich first. He gave a rhetorically strong answer, defending “capitalism.” But if Romney had any sense, he would remind people that Gingrich’s Super PAC produced the Michael Moore-like video attacking Romney. Romney’s lines defending capitalism are powerful, but he’s missing an opportunity to hang the anti-capitalist albatross around Gingrich’s neck.
Good Reagan Democrat lines from Santorum: “I believe in capitalism for everybody … capitalism that works for the working men and women of this country.”
UPDATE.4: We’re half an hour into this debate, and Romney is pretty much inert versus Gingrich. True, Gingrich hasn’t attacked him, but Gingrich has momentum now. What’s his thinking here? I don’t understand it. What is Romney afraid of? Or perhaps more relevantly, given his calculating, disciplined nature, what is he thinking? I’m not seeing the ads airing in South Carolina; is it the case that he thinks his paid media will do the dirty work for him in SC, while he can maintain a cleaner image nationally via this televised debate? What do you think?
UPDATE.5: Michael Brendan Dougherty says the debate is over and Gingrich won  with that fiery response. Excerpt:
It was obvious that Gingrich was ready for the question, and absolutely ready to pounce all over it. The surprise here is that his accusation that the media makes it “harder to govern” this country, and harder to attract “decent” people was so easily swallowed by the audience from a twice-divorced, two-timer like Newt Gingrich.
Santorum is on fire against Romney and Gingrich on the health care question. Clearest, crispest thing I’ve heard him say in ages.
UPDATE.6: MBD tweets: 
It’s pathetic that conservatives are cheering a twice-adulterer implying to them than HE’S the decent one.
UPDATE.7: I’m not entirely clear on something. Is Ron Paul suggesting that we redeploy US soldiers to bedpan duty for Medicare recipients?
UPDATE.8: Why does Gingrich think that his starting a healthcare lobbying outfit makes him an expert on healthcare?
UPDATE.9: Santorum: “Grandiosity has never been a problem with Newt Gingrich. … I don’t want a nominee that I have to open the morning papers worrying about what he’s going to say next.”
More: “I’m steady, I’m solid, I’m not going to go out there and do things that you’re going to worry about.” Excellent. Santorum identifies the big worry about Gingrich. He’s got to hit on this harder if he wants to have a shot.
Gingrich had an effective response, including: “You’re right: I think grandiose thoughts. This is a big country with big people doing big things.”
Santorum a great retort: “Four years into his leadership, he was thrown out by the conservatives.” Santorum reminds people that he was in the House working with Gingrich, and saw, “No discipline, no ability to be able to pull things together.” And he rips the hell out of Gingrich for his flawed Congressional leadership. Very, very strong stuff.
But Gingrich is unbowed. “I think long before Rick came to Congress, I was busy being a rebel… .”
Santorum gave it a great shot, and what he says is true. But Gingrich, being shameless, probably did okay.
Good grief, Romney, Santorum gave you a terrific opening to savage Gingrich, but all you can come up with are these idiotic robo-lines about needing a non-Washington person to be president! Look, there’s a great Romney line about how Gingrich didn’t show up in the Reagan diaries, which belies Gingrich’s claim to have been a big Reaganite — but Romney stepped on his own line. He’s awful.
UPDATE.10: Gingrich is rocking hard tonight. Unless the Marianne interview is a blockbuster — and Newt has done a good a job as he can insulating himself among GOP primary voters — I think he’s going to win South Carolina. Romney can’t lay a glove on him. Romney looks so weaselly on the tax return question, and he is weaselly on this issue.
UPDATE.11: Newt, terrifically sarcastic on the SOPA question: “You’re asking a conservative about the economic interests of Hollywood.” And then he gives a good political answer about being for “freedom.” Gingrich is walking away with this thing tonight.
Santorum makes a decent point that property rights are important. His statement that the idea that the Internet ought to be a free for all is nuts surely comes out of the way he has been so disgustingly abused by Dan Savage’s internet campaign against him.
UPDATE.12: John Podhoretz tweets: 
Not watching but based on what I’m reading, how is it that Romney has spent 5 years running without a strategy for talking about being rich?
UPDATE.13: Romney is such a tool, saying he wish he had talked about his opponents less and Barack Obama more. What a smarmy answer. Does he even realize he is in a race against Newt Gingrich? Does he realize that Gingrich is kicking his butt tonight?
UPDATE.14: Ron Paul is a non-entity tonight.
UPDATE.15: If Santorum had been as good earlier in this race as he’s been in these last two debates, he might have gotten a lot further by now. If he had whiffed tonight, I’d say it was a huge win for Newt. But he’s been good. I still believe that Gingrich wins this thing, because he’s had the applause lines tonight. This comment from an Andrew Sullivan reader caught my eye, though:
You know, in the end, Santorum just doesn’t have the balls to duke it out with Gingrich and Romney. He gets out there and throws that big first shots and they’re good ones, but when he gets hit back, he starts to falter a little. You can see it in his body language. Newt and Romney throw their usual bullsh*t at him and it’s bullsh*t, but they do it with their usual arrogance and ego and it starts to overwhelm Santorum. He’s not long for this race.
UPDATE.16: I think Romney’s answer on the pro-life point was acceptable. But why on earth doesn’t he round on Newt? Santorum was terrific on the abortion question, both against Romney and Gingrich.
UPDATE.17: Good for the audience, forcing John King to let Ron Paul answer the abortion question. “Law will not correct the basic problem, and that’s the morality of the people” — Ron Paul, making a useful point.
I don’t agree with Paul’s view on abortion rights, but I do appreciate very much his consistency on Constitutionalism.
UPDATE.18: Gingrich’s final statement was completely hysterical and absurd, but as a matter of GOP primary politics, he made an effective case for why he’s the man to go up against Obama, not the uncertain Romney. Understand, I think Gingrich would be a disastrous candidate against Obama, but if one is voting on heart, not head, Gingrich wins.
Santorum made a very strong case for himself, as the kind of candidate who can win the Reagan Democrats.
OK, debate over, and here’s my quick take: Romney lost badly. But because Santorum and Gingrich were equally good, it might well have meant a Romney win on election day — this, if it divides the anti-Romney vote. Because Gingrich has the momentum, I have to think he helped himself the most tonight. I think he did a terrific job insulating himself with GOP voters against the Marianne bombshell — and that’s going to be the biggest talking point of the next news cycle.
CNN just going through a highlights reel right now. There were a number of powerful lines from Santorum and Gingrich. All the Romney highlights are unfavorable to himself. I just can’t see anybody who is for Romney being excited about this cat.