This is the last debate for almost a month, and it's the first debate since Santorum started taking the lead in national polls. So the pressure is on.
I'll be live-blogging here. Keep reloading for more updates.
For more live-blogging, check out TalkingPointsMemo or National Review.
You can watch the debate live online at CNN's homepage.
As always, any quotes in this post are written down on the fly, without a transcript or a pause/rewind button. They may not be verbatim, but I'll try to keep them reasonably accurate.
8:07 - The candidates are all sitting down, unlike all the other debates on the major cable news networks.
8:08 - Mitt Romney cuts short his own introduction: "As George Costanza would say, when they're applauding, stop." [UPDATE: Jason (the commenter) points out that Romney was referring to this episode of Seinfeld:
At the coffee shop, George laments to Jerry about losing respect at a project meeting led by Mr. Kruger after following a good suggestion with a bad joke. . . . At the next Kruger meeting, George takes Jerry's suggestion and actually leaves the room after a well-received joke.]8:18 - Ron Paul is asked why he has released an ad calling Rick Santorum "a fake." His answer: "Because he's a fake." Santorum, who's sitting right next to Paul, holds out his arms and says: "I'm real!"
8:22 - Romney is asked why said he was a "severely conservative governor." He massages his unfortunate word choice: "severe — strict." Then he segues into fiscal conservatism.
8:29 - Rick Santorum spends a long time defending earmarks, which seems like a questionable strategy in the Republican primaries. Romney responds dismissively: "I didn't follow all that."
8:33 - The discussion of earmarks is very chaotic, with lots of crosstalk and booing of Romney and Santorum. There doesn't seem to be any dramatic difference of opinion among any of the candidates. None of them seem to be taking the John McCain approach of opposing the whole process of earmarks on principle.
8:42 - Paul takes issue with people who say the bailout of General Motors worked: "That's like saying someone who robbed a bank was successful! You still broke the law to do it."
8:46 - All the candidates are asked whether they "believe in birth control." The audience boos loudly. In a bizarre non sequitur, Gingrich says that no one in the media in 2008 asked Barack Obama why he supported "infanticide."
8:50 - Santorum is asked what he meant by talking about "the dangers of contraception" on the campaign trail. He claims that "the New York Times was talking about the same thing" recently in a review of Charles Murray's book on the white underclass. He doesn't explain what that has to do with contraception. He adds: "Just because I'm talking about it doesn't mean that I want a government program to fix it." That's disingenuous. Right after explaining why he thinks contraception is "not okay," Santorum added that "these are important public policy issues." What else did he mean by those words if not that he would like to see some kind of public policy change to deal with the problem of contraception?
9:02 - Romney tries out a desperate new argument against Santorum: he supported Senator Arlen Specter, who's from Santorum's state of Pennsylvania and cast a deciding vote in favor of Obamacare. So instead of criticizing Romney for providing a model for Obamacare, Santorum should "look in the mirror."
9:21 - All the candidates are asked to define themselves in just one word. Paul: "Consistent." Santorum: "Courage." Romney: "Resolute." Gingrich: "Cheerful."
9:52 - The candidates are asked what the biggest misconception about each of them is. Paul: "That I can't win." He mentions a poll where he does the best in a match-up against President Obama. Gingrich: They don't understand how much work it took for him to achieve welfare reform and a balanced budget (under President Clinton). Romney: That his record or positions on specific issues are more important than his overall leadership qualities. Santorum dodges the question, but says he's shown that he "can do a lot with a little": he doesn't have much money but he's still winning.
That's all for tonight, and that might be all until the general election.