Jacksonville, Florida (CNN) -- After a stunning loss in South Carolina and an uneven performance in a debate on Monday, Mitt Romney appeared to get his swagger back and turned in a strong performance in Thursday's CNN/Republican Party of Florida debate. Here are five things we learned Thursday night.
Romney came to play
On the heels of his drubbing in South Carolina, Romney stabilized in the polls this week and now appears to be holding a comfortable lead in Florida. His renewed sense of confidence was on display Thursday night.
Romney, in what may have been his sharpest debate performance of the campaign, quickly put Gingrich on his heels with a swift 1-2 punch out of the gate.
First, he drew applause by forcefully brushing back Gingrich's claim that he is the most "anti-immigrant" candidate in the Republican field.
"Mr. Speaker, I'm not anti-immigrant," Romney said. "My father was born in Mexico. My wife's father was born in Wales. They came to this country. The idea that I'm anti-immigrant is repulsive. Don't use a term like that."
Amid the cheers, Gingrich seemed baffled that the debate crowd was siding with Romney instead of him.
Moments later, Romney was prepared when Gingrich tried to highlight Romney's personal investments in Fannie Mae and Freddie Mac in an effort to cast Romney as a hypocrite.
Romney has spent several days going after Gingrich for giving paid advice to the federally backed mortgage firm Freddie Mac ahead of the national housing meltdown, which led to a wave of foreclosures in Florida. Gingrich tried to fight back in the debate.
"Have you checked your own investments?" Romney retorted after Gingrich called attention to the mutual fund investments. "You also have investments through mutual funds that also invest in Fannie Mae and Freddie Mac."
A stone-faced Gingrich had no answer.
Also working in Romney's favor: a new debate coach, former Michele Bachmann adviser Brett O'Donnell.
O'Donnell told CNN that Romney realized after South Carolina that he needed to "make some changes strategically" in his onstage message.
"He knew he had to engage Newt more and be better on a couple of answers," O'Donnell said. "He worked really hard to get them right, and tonight I saw a vast improvement."
Gingrich steps in immigration quicksand
Gingrich's most dramatic exchange with Romney came when discussing the sensitive topic of illegal immigration. He decided to stake out a position to the left of Romney.
Moderator Wolf Blitzer asked Gingrich to explain a radio ad calling Romney "the most anti-immigrant candidate" in the race.
Gingrich suggested Romney's illegal immigration positions are so tough that he would storm churches and deport helpless grandmothers. He called for an immigration policy with "some level of humanity."
Romney fired back.
"You know, our problem is not 11 million grandmothers," he said. "Our problem is 11 million people getting jobs that many Americans, legal immigrants, would like to have."
The debate theater erupted in applause for Romney.
Hispanic voters comprise about a tenth of Republican primary voters in Florida, and the candidates have noticeably softened their immigration rhetoric on the trail this week as a result.
But as Rick Perry discovered in a Florida debate last fall when he said immigration hardliners don't "have a heart," drifting too far to the left of the conservative base can be a risky proposition in the Sunshine State.
Perry cratered in the polls soon after making that remark.
Gingrich's decision to spar at length with Romney over whether illegal immigrants deserve to stay in the country was a tactical blunder in a Republican primary, simply because he helped Romney look more conservative.
One of Gingrich's campaign co-chairs in Florida, former Attorney General Bill McCollum, conceded that it was not one of Gingrich's best nights.
"I don't think he hurt himself," McCollum said. "I just don't think he helped himself as much as he did in South Carolina."
Gingrich's opponents have mocked him for offering policy ideas that can sometimes seem farfetched, nonsensical or just plain strange.
Gingrich has always been a proponent of space exploration, but his plan to install an American colony on the moon by the end of his second term in office was roundly attacked on Thursday.
In a time of fiscal austerity, when NASA is facing deep cuts, the Republican candidates agreed that his proposal is outlandish and too costly for the country.
Romney: "That's an enormous expense. And right now I want to be spending money here."
Rick Santorum: "Those are things that sound good and maybe make big promises to people, but we've got to be responsible in the way we allocate our resources."
Ron Paul: "Health care or something else deserves a lot more priority than going to the moon."
Gingrich responded by calling on Americans to think big. He said lunar exploration could be affordable with some clever budget tinkering.
But with Republican voters still pointing to jobs and the economy as their main concern, Gingrich's vigorous defense of moon science seemed like a sideshow.
Paul plays the charmer
While the rest of the candidates were battering each other with tough words and harsh accusations, Ron Paul killed them with kindness.
Though he sometimes comes off as cantankerous and overly excitable, Paul was charming, witty and warm on Thursday. His sense of humor was finely tuned, even when criticizing his foes.
Responding to Gingrich's space talk, Paul joked: "I don't think we should go to the moon. I think we maybe should send some politicians up there."
When Blitzer asked the 76-year old Paul if he would release his medical records, Paul offered an enthusiastic yes.
"I'm willing to challenge any of these gentlemen up here to a 25-mile bike ride any time of the day in the heat of Texas," he said, eliciting laughter from the rest of the candidates.
He even managed to work in a plug a cookbook authored by his wife, "The Ron Paul Cookbook."
However, Paul was certainly not just comic relief. He won cheers for promising to slash the budget by a trillion dollars and concisely delivered his arguments for reducing the size of Washington. It was one of his best debate nights in months.
Santorum strikes again
Remember Romneycare? The health care plan that Romney signed into law in Massachusetts -- which bears a striking resemblance to the one President Barack Obama implemented at the federal level -- somehow keeps falling by the wayside in the Republican race.
The task of reminding Republicans about the plan fell to Santorum, who continues to shine in the debates.
In the most pointed takedown of Romneycare to date, Santorum did a masterful job of pointing out the similarities between the two laws as he made the case that Romney would not represent a strong enough contrast to Obama in the general election.
He somehow goaded Romney into defending, before a national audience, the importance of health insurance mandates in Massachusetts (though he opposes them nationally).
Romney then said that the health care debate "is not worth getting angry about" -- a comment that elicited some grumbling from the Republican crowd.
Santorum, trailing in the polls and in desperate need of a big night, seized the moment.
"What Governor Romney just said is that government-run top-down medicine is working pretty well in Massachusetts and he supports it," he said. "Now, think about what that means. Going up against Barack Obama, who you are going to claim, well, top-down government-run medicine on the federal level doesn't work and we should repeal it. And he's going to say, wait a minute, Governor. You just said that top-down government-run medicine in Massachusetts works well."
Democrats on Twitter were positively giddy after the back-and-forth.
"In explaining MA plan, Mitt just offered an eloquent explanation of the Affordable Care Act he says he would repeal," tweeted Obama adviser David Axelrod.