DEBATE NIGHT: Can Mitt Romney get under Newt Gingrich's skin?

Mitt Romney will use Monday night’s GOP debate in Florida to try to get under Newt Gingrich’s skin.

Romney, who was trounced by Gingrich in Saturday’s South Carolina primary, has lost momentum and the veneer of being the inevitable GOP presidential candidate.

To get it back, Romney is focused on attacking Gingrich, whom he hopes will make an unforced error if he’s put under pressure.

Romney was relentless Monday in his attacks on Gingrich’s House ethics record and his ties to Freddie Mac. He worked hard to paint Gingrich as an unstable candidate bound to crack in the White House.

"With Newt Gingrich, it's an October surprise every day," Romney said on Fox News Monday morning.

A similarly aggressive Romney can be expected on Monday night.

“I think Romney is going to try everything he can to bring out ‘Bad Newt,’” said Claremont McKenna College Professor Jack Pitney, who worked under Gingrich on Capitol Hill in the 1980s. “I’m sure he and his advisers are plotting ways to get inside his head.

“We’re going to see psychological warfare as well as rhetorical warfare,” Pitney said.

How Gingrich reacts to Romney’s barbs could determine who wins the debate.

“Gingrich does well when he puts on a show of aggressiveness. He does not do well when he is genuinely angry,” said Pitney. “Romney wants to play with Newt’s head and make it explode.”

Romney on Monday blasted Gingrich as a former lobbyist and demanded he release the full documentation of what he did for mortgage giant Freddie Mac, a line of attack that could prove a winner in Florida, hit hard by the mortgage crisis.

"Let's make sure that we understand what was in the work product that he was providing to Freddie Mac. What was the contract, what did they pay him for?” Romney said.

He also mocked Gingrich’s claim that he’s mostly worked as a historian.

“You don't pay someone $1.7 million just to write his history,” Romney said. “Did he write their history? Let's see the work product. Did he lay out their history, or did he write policy and provide access to people in power?"

Romney’s debate strengths so far have been in deflecting others’ attacks and staying on message rather than taking shots at others. He’s mostly stayed above the fray, and while he won a few exchanges with Rick Perry over immigration this fall, the Texas governor — who bowed out of the presidential contest last week — is a notoriously weak debater. Romney will need to show he can be adept at counter-punching and keeping his cool while irritating Gingrich.

Gingrich, for his part, needs to keep his famous temper in check and have another debate performance like the last two, which helped him win South Carolina. A similar performance on Monday could help catapult him to a win in Florida. But if he comes across as angry or petulant, it could hurt his campaign.

Of course, Gingrich and Romney won’t be the only people on stage. Texas Rep. Ron Paul and former Pennsylvania Sen. Rick Santorum will round out the crowd, and Santorum’s performance could also be a major factor.

Santorum had some effective hits against both Romney and Gingrich at Thursday night’s debate, but failed to focus on one candidate and take them down. He also continued to fight with Paul rather than focus on the front-runners in the state.

Gingrich’s rise has come at Santorum’s expense: the two are competing over the more conservative voters who are resistant to Romney. If Santorum hopes to claw his way back into the race he needs to take down Gingrich.

“The question is whether Santorum will aim the nastiness more at Newt or Romney,” said Pitney. “Santorum is in a good position to talk about Gingrich’s record in the House because he served with Gingrich and was watching him up close.”

Paul could also affect the debate, although he has been largely ignored by moderators. If he can echo what his television ads have been saying, hit him on Freddie Mac and paint him as a “serial hypocrite,” he could help trigger Gingrich’s anger. But he not been much of an attack dog in debates so far, save for strong reactions to attacks on his own foreign policy views.

In the end, Monday’s focus will turn back to Gingrich and Romney, as one of the two seems most like to emerge with a win in Florida. How Gingrich handles Romney’s attacks, and how Romney handles the counterattacks, could go along way toward deciding who finishes first in next week’s primary.