How many Republican presidential primary debates have we had? How many over-the-top introductions by booming voice-overs have we had to sit through? A dozen.

That’s a lot of TV time. And after all that the Republican electorate remains very conflicted about who should be the party’s presidential nominee. A few candidates have wilted under the pressure of frequent debates and the need to speak in complete sentences. Two contenders have left the race. (By the way, wasn’t Herman Cain going to endorse Newt Gingrich?) One of those, Tim Pawlenty, seems pretty good in retrospect.

Some of the bobbles are hard to remember. (Was Rep. Michele Bachmann’s confusion over the HPV vaccine, actually uttered after a debate, her great slip-up? Gosh, that seems minor compared to the disasters that followed.) And other goofs left indelible marks (e.g. Texas Gov. Rick Perry’s flubs). In essence, the debates have helped weed out candidates and elevate others but haven’t helped settle the race.

That’s not surprising, of course. Debating skill is one factor in choosing a nominee, one that reveals verbal dexterity and knowledge. However, a candidate’s record, character and response to adversity are larger concerns that transcend these duels.

Tonight’s debate will be the last of 2011 and will help set the race heading into the holiday season, when it becomes more difficult to communicate political messages and many voters tune out politics for a time. If first impressions are critical, final ones are, too. And given how fluid the Iowa race is, everyone will be straining to avoid errors and to cause his or her opponents to fumble.

For Newt Gingrich the task is to figure out how to walk back his obnoxious attacks from the left on both Rep. Paul Ryan (R-Wis.) and Mitt Romney. Contrition is not his strong suit, but these were big errors that affect conservative voters, so he better be willing to eat some crow. In the last couple of weeks his rivals have dump a load of negative information on the voters; Gingrich will now have to remind voters of his positive message and the rationale for his candidacy. (Something about setting up a big contrast with the president and firing up the base, I suppose.) He’ll do himself more harm if he digs in on his attacks or if he shows that telltale thin-skinnedness. He will need to be gracious if asked about the influential conservative magazine National Review’s anybody-but-Newt endorsement. His instinct will be to insult and jab back at the conservative flagship, but that would only confirm the truth of its editors’ conclusion. (“Gingrich has always said he wants to transform the country. He appears unable to transform, or even govern, himself. He should be an adviser to the Republican party, but not again its head.”)

The media convinced themselves that Gingrich “won” the last debate, but in fact he only opened the door to withering attacks. He can’t afford another media “win” like the last one. The problem he has is a not uncommon one for a pol with a massive ego and thin skin: He doesn’t wear well. He better start reassuring voters and stop antagonizing key players on the right.

Mitt Romney, on the other hand, is on a bit of a roll. He’s zinging Gingrich for sounding like a lefty, dredging up that Newt-Nancy ad and getting a helping hand from Ryan, who didn’t appreciate Gingrich’s “suicide” crack. He can’t afford to lose his temper either and needs to give a steady performance emphasizing the contrast between his business background and Gingrich’s insider status. And frankly, Romney would be more than happy to see Reps. Ron Paul (R-Tex.)or Bachmann (R-Minn.) have a good night, or see Rick Santorum’s standing continue to rise. The more votes Gingrich loses, the better for everyone else.

Paul has the potential to win Iowa, which might be very bad for Iowans trying to keep their contest in first position in future primary races but very good for him. He’s been taunting and attacking Gingrich in ads and is well positioned to paint Gingrich as an advocate of big government. He’d do well to put a lid on his gold standard talk and stay away from foreign policy, which is a bridge too far for most Republicans. At least for now, a Romney and Paul anti-Newt alliance is in both Paul’s and Romney’s interest. Watch for him to bait and attack Gingrich.

There’s wide disagreement among Iowa watchers as to whether Perry is making a move. He has climbed back into double digits in the Iowa polls, but it’s not clear how intense his support is or how capable his ground game is. In the debate he can’t afford more pregnant pauses or moments of policy confusion. He’ll play the Washington outsider angle to the hilt. He will have difficulty staying in the race if he finishes behind Bachmann and/or Santorum, so he might feel compelled to take a few swats at those candidates.

Santorum has reason to be pleased with his last debate performance. Santorum has been racking up local endorsements and is trying to snag one from social conservative leader Bob Vander Plaats, who heads the Family Leader group. If he could pull that off it would be a huge coup. In the debate he will need to bring the sunnier, softer Santorum, not the Santorum who complains about equal time and can’t resist reminding us of his credentials. When he answers the questions directly and forcefully, while weaving in local references and social issues, he is as good as anyone on the stage. For Santorum, he might get some mileage out of going straight at Gingrich, mocking Gingrich’s claim to consistency and conservatism. But he needs to do it with a smile on his face and a scalpel, not a sledgehammer.

Finally, Bachmann, like Santorum, is coming off a very solid debate in Des Moines. She did the best job of tying together the two front-runners (“Newt Romney”) while styling herself as a fighter for the Tea Party. She’s got a bit more flair than Perry and Santorum, and if she can avoid a last-minute stumble she could finish solidly in the caucuses and get herself back into the race.

The biggest problem for Gingrich is high expectations. He is supposed to be the best debater and is expected to win Iowa going away. If you don’t believe it, he’ll tell you so. With every candidate trying to provoke and skewer him he’ll need a steady and uneventful performance. And then he’ll have to hope the anti-Gingrich momentum stalls during the holidays. Otherwise, he may become just another in the long list of anti-Romney contenders.