Moon base! Freddie! Self-deportation! The GOP debate’s top 5 moments

“When I’m shot at, I’ll return fire. I’m no shrinking violet,” Mitt Romney said after Thursday night’s Republican presidential debate, the final one before voters go to the polls in next week’s Florida primary.

By most accounts, the former Massachusetts governor had a strong night. He stayed on the offensive against his top rival, Newt Gingrich, seemingly determined not to deny Gingrich a chance to play the role of the bully on the block. And when Romney was attacked -- either by Gingrich or Rick Santorum or Ron Paul -- he effectively swatted them away.

Because of that, the debate at the University of North Florida had its share of incendiary moments. Here’s a look at five of the testiest exchanges:

1) Romney fumes at being called ‘anti-immigrant’

The debate got heated early when moderator Wolf Blitzer of CNN raised Romney’s claim that identity cards and an e-verify program would discourage illegal immigrants from trying to work here, and that many would eventually “self-deport.” Did Gingrich still stand by his accusation that Romney’s plan amounted to an “Obama-level fantasy”?

Self-deportation, Gingrich said, would occur “if you’re single and have only been here a short period of time.” But people who have been here many years -- “grandmothers and grandfathers,” as Gingrich often puts it -- will never leave their families, he said. Those people, he added, should be able to get residency, if they can find American families to sponsor them.

Blitzer asked Romney why he thinks the concept of self-deportation would work. Romney said it would be a process that would happen “over time.”

“I don’t think anyone wants to go around deporting 11 million Americans, excuse me, illegal immigrants,” Romney replied, laying out his plan for identification cards and an e-verify system. “Let’s focus our attention on how to make legal immigration work and stop illegal immigration.”

Blitzer asked Gingrich to explain why he described Romney as the “most anti-immigrant candidate.”

Again, Gingrich raised the idea that illegal immigrants with roots in the U.S. will simply never leave.

“They will end up in a church, which will declare them a sanctuary,” he said. “You have to be realistic in your indignation. I want to control the border. I want English to be the official language. I want to be bold but realistic.”

But Blitzer pressed him on his description of Romney: “Is he still the most anti-immigrant candidate?”

“Yes,” replied Gingrich, setting off what can only be described as a controlled tirade by Romney.

“That’s inexcusable,” Romney fumed. “My father was born in Mexico, my wife’s father was born in Wales. The idea that I am anti-immigrant is repulsive.”

He added that the description “is simply the kind of over-the-top rhetoric that has characterized American politics for too long. ... Having a difference of opinion does not justify labeling people with highly charged epithets.”

Gingrich was unruffled: “Tell me the language, if you think it’s OK to deport grandfathers and grandmothers.”

“I am not running around rounding up people and deporting them,” Romney said. “People who come legally get a work permit; those who don’t over time will self-deport.”

“All I want to do,” retorted Gingrich, “is allow the grandmothers to be here legally with some rights to have residency but not citizenship, so that he or she can finish their life with dignity within the law.”

“Our problem is not 11 million grandmothers,” Romney said. “Our problem is 11 million people getting jobs that many Americans, legal immigrants, would like to have.”

2) Fanning the flames over Fannie and Freddie

After trading jabs all week over the political liabilities each had accrued during their time in the private sector, Romney and Gingrich went at it over their respective ties to mortgage giants Fannie Mae and Freddie Mac.

Gingrich attacked Romney for his investments in the mortgage companies and for investing in Goldman Sachs, “which is today foreclosing on Floridians.” Romney has blasted the former House speaker for his past work as a consultant for Freddie Mac.

“First of all, my investments are not made by me,” Romney replied, referring to his blind trust, which is operated by a trustee.

“Have you ever checked your own investments?” Romney asked Gingrich. “You also have investments in mutual funds that also invest in Fannie Mae and Freddie Mac.”

“What the speaker did was to work as a spokesman to promote Fannie Mae and Freddie Mac,” Romney said.

Gingrich shot back with a reference to Romney’s earlier assertion that he hadn’t seen an ad -- run on Romney’s behalf -- that slammed Gingrich for suggesting that Spanish is “the language of the ghetto.”

Blitzer had earlier told Romney that fact-checkers had determined that the ad carried Romney’s on-camera approval.

“First of all, you’ll notice that the governor wasn’t aware of the ad he was running,” Gingrich said. “He was not aware of the investments that were being made in his name ...”

Romney cut in: “Of course I can’t -- that’s a blind trust.”

“To compare my investments with his is like comparing a tiny mouse with a giant elephant,” Gingrich said.

3) Defending the healthcare mandate

Santorum took on Romney for his embrace of a universal healthcare mandate in Massachusetts, saying Romney would be an ineffective opponent against President Obama because both had backed “government-run, top-down medicine.”

“Those are not the clear contrasts we are going to need if we are going to defeat Barack Obama,” Santorum said.

“I didn’t say I was in favor of top-down, government-run healthcare,” Romney said. Most of the 92% of Massachusetts residents who already had health insurance kept their plans or were able to buy policies from private insurers, he said. To the 8% who lacked insurance, Romney said, his plan sent a clear message: “If you don’t want to buy insurance, you have to help pay for the cost of the state picking up your bill. ... We said no more free riders. ... Either get the insurance or help pay for your care.”

Santorum zeroed in like a prosecutor: “So ... everybody is mandated as a condition of breathing in Massachusetts to be able to buy health insurance, and if you don’t, you have to pay a fine. What’s happened in Massachusetts is people are not paying the fine. ... Free ridership has gone up five-fold in Massachusetts.”

Romney seemed on the verge of responding with an epithet: “That’s total ... “

Then he pulled back.

“First of all, it’s not worth getting angry about,” though it was unclear whether he was addressing Santorum or himself.

Romney pivoted back to Obama and his administration healthcare legislation: “What he did was wrong; it’s bad medicine, it’s bad for the economy, and I will repeal it.”

But Santorum could not resist a final shot: “What Gov. Romney said is just factually incorrect. Your mandate is no different than Barack Obama’s mandate. It is the same mandate.”

At that point, Paul weighed in: “I think they’re all wrong. This is a typical result of when you get government involved, because all you are arguing about is which form of government you want. They have way too much confidence in government sorting this out.”

4) Gingrich gets Blitzered

One week after Gingrich savaged CNN’s John King for an opening debate question about allegations raised by the former congressman’s ex-wife, his attempt to deflect a question about attacks on Mitt Romney was turned against him by a different CNN anchor.

Blitzer asked Gingrich whether he was satisfied with the level of disclosure Romney had provided about his personal finances. Gingrich called it a “nonsense question,” and the crowd roared in approval.

“How about if the four of us agree for the rest of the evening we’ll actually talk about issues that relate to governing America?” Gingrich said.

Blitzer wasn’t about to let Gingrich off the hook, quoting Gingrich’s own rhetoric about Romney’s “Swiss bank and Cayman Island bank accounts.”

“I didn’t say that, you did,” Blitzer said.

“I did. And I’m perfectly happy to say that in an interview on some TV show. But this is a national debate where you have a chance to get the four of us to talk about a whole range of issues,” Gingrich responded.

“If you make a serious accusation against Gov. Romney like that, you need to explain that,” Blitzer fired back.

The audience booed Blitzer, much as they did King a week before.

But this time, Romney piled on his GOP rival.

“Wouldn’t it be nice if people didn’t make accusations somewhere else that they weren’t willing to defend here?” he asked.

Gingrich finally obliged, and repeated his view that it was “unusual” for a would-be president to have a Swiss bank account.

“I have a trustee that manages my investments in a blind trust,” Romney again explained. And that trustee did invest in a Swiss account, one that was reported and on which full taxes were paid, he added.

“There’s nothing wrong with that. And I know that there may be some who try and make a deal of that, as you have publicly. But I think it’s important for people to make sure that we don’t castigate individuals who’ve been successful,” he said to Gingrich.

“Let’s put behind this idea of attacking me because of my investments or my money, and let’s get Republicans to say, ‘You know what, what you’ve accomplished in your life should not be seen as a detriment. It should be seen as an asset to help America.’”

The crowd then cheered on Romney.

“Mr. Speaker, I’m ready to move on if you are,” Blitzer then said to Gingrich, and the former lawmaker responded by asking for “a two-way truce” with Romney about personal attacks.

5) The man in the moon

Surely the most enjoyable moment of the evening was a lengthy, lengthy exchange about Gingrich’s pledge that if he is elected president America would have a base on the moon, otherwise risking losing the satellite to China.

With the U.S. economy struggling and the country engaged in war overseas, it might seem odd that a significant portion of a presidential debate was taken up with talk of a moon colony, but Florida does take its role in the American space program seriously. So at least there was some kind of a hook.

Still, the other candidates, led by Romney, gleefully pour cold water on Gingrich’s lunar dreams.

“That’s an enormous expense. And right now I want to be spending money here. Of course the space coast has been badly hurt, and I believe in a very vibrant and strong space program,” Romney said. “I’m not looking for a colony on the moon. I think the cost of that would be in the hundreds of billions, if not trillions. I’d rather be rebuilding housing here in the U.S.”

Gingrich was asked how in the world (or the moon) he would keep taxes down but see a moon base built.

The audience laughed. Gingrich said he would offer prizes.

“There are many things you can do to leverage accelerating the development of space. Lindbergh flew to Paris for a $25,000 prize. If we had a handful of serious prizes, you’d see an extraordinary number of people out there trying to get to the moon first,” he said. “And I’d like to have an American on the moon before the Chinese get there.”

Santorum said the cutting the federal budget had to take priority.

“Let’s just be honest, we run a $1.2-trillion deficit right now,” he said. “ ... We’re borrowing 40-cents of every dollar. And to go out there and promise new programs and big ideas, that’s a great thing to maybe get votes, but it’s not a responsible thing when you have to go out and say that we have to start cutting programs, not talking about how to grow them.”

And Paul, as his did many times over the course of the evening, had a one-liner ready.

“Well, I don’t think we should go to the moon. I think we maybe should send some politicians up there,” he said.

But Gingrich wouldn’t back down, despite a growing sense among observers that perhaps his best move would be to move on to another topic -- and fast. This was Futurist Newt, the self-described visionary, the big-idea man that both his detractors and supporters expected to surface at some point and perhaps scuttle his presidential hopes.

Blitzer repeated Gingrich’s assertions that someday 13,000 Americans could be living on the moon and that they could apply for “U.S. statehood.”

“The program I envision would probably end up being 90% private sector, but it would be based on a desire to change the government rules and change the government regulations, to get NASA out of the business of trying to run rockets, and to create a system where it’s easy for private-sector people to be engaged,” Gingrich said.

“I want to see us move from one launch occasionally to six or seven launches a day because so many private enterprises walk up and say, ‘We’re prepared to go do it.’ But I’ll tell you, I do not want to be the country that, having gotten to the moon first, turned around and said, ‘It doesn’t really matter, let the Chinese dominate space, what do we care?’ I think that is a path of national decline, and I am for America being a great country, not a country in decline.”

It all sounded lofty, aspirational, Kennedyesque, but the practical Romney was ready.

“I spent 25 years in business,” he said. “If I had a business executive come to me and say they wanted to spend a few hundred billion dollars to put a colony on the moon, I’d say, ‘You’re fired.’”