Former Massachusetts Gov. Mitt Romney, Texas Rep. Ron Paul, former House Speaker New Gingrich and former Pennsylvania Sen. Rick Santorum went all out during last night's Florida Republican debate.

The four remaining candidates tackled a broad range of foreign, domestic and social issues, including foreign intervention in Latin America, Romney's links to Obamacare, illegal immigration, and Gingrich's work for Fannie Mae and Freddie Mac.

Relive some of the highlights from the CNN-sponsored event below, and get a rundown of the top quotes and biggest arguments at last night's debate. The Florida 2012 Republican Primary will be held next Tuesday, on Jan. 31.

Mitt Romney

The former Massachusetts governor made a strong showing last night, but his conversations with Newt Gingrich got very ugly, very fast. He went after the former House Speaker for his moon colony plan and his work as a consultant for Fannie Mae and Freddie Mac. And when Gingrich accused Romney of being anti-immigrant, the usually composed candidate lost his cool.

1. To say that I'm anti-immigrant is repulsive.

When Mitt Romney's self deportation plan came up again during tonight's debate, Newt Gingrich accused him once again of being anti-immigrant, and claimed that his plan would only exacerbate the illegal immigration problem in the U.S. Romney, whose father is a Mexican immigrant and whose mother's family is from Wales, said he found the epithet inexcusable.

To say that I'm anti-immigrant is repulsive, he told Gingrich. He voiced similar disgust for a campaign ad where Gingrich claimed Romney had no concern for the humanity of illegal immigrants. I'm glad that Marco Rubio called you out on it. I'm glad you withdrew [the ad]. I think you should apologize.

2. Our problem is not 11 million grandmothers.

The Romney-Gingrich immigration debate continued when Gingrich claimed Romney's self deportation plan ignored the families who had lived in America for generations. Young single people could leave and apply for citizenship, Gingrich said, but is it really reasonable to expect grandmothers and grandfathers would do so?

Our problem is not 11 million grandmothers, Romney shot back, to significant applause.

3. Have you checked your investments?

When Mitt Romney tried to bring Gingrich's ties to Fannie Mae and Freddie Mac back into the spotlight, the former Speaker bit back. Romney's financial records, released this week, revealed that Romney had invested in Mac and Mae. How many homes had been foreclosed in Florida because of that investment?

Romney countered that he didn't invest in those companies at all. They were made through a blind trust, and were part of a mutual fund set up by a trustee. But Mr. Speaker, have you checked your investments? Romney said. He argued that their financial commitments to Freddie and Fannie, at least as far as investments go, were almost exactly the same.

4. It may be a big idea, but it's not a good idea.

Romney tore into Gingrich's moon colony plan from his time as House Speaker.

I'm not looking for a colony on the moon, he said. I'd rather be rebuilding housing here in the U.S.

5. ...what people want to hear.

Romney accused Gingrich of going state to state, and promising what people want to hear, no matter how much it would cost taxpayers. In Florida, Gingrich advocates expanding NASA. In South Carolina, it was working on an interstate highway.

That's what got us into the trouble we're in now, Romney argued. We've got to say no to this kind of spending.

Ron Paul

The Texas congressman continued to be the firecracker candidate this round. He was the only candidate to advocate warming relations between the U.S. and Cuba, and the only one to warn against overreaction and overconcern in other countries' affairs. In the realm of Fannie Mae and Freddie Mac, he refused to dig into questions of his rival's finances. And when moderator Wolf Blitzer asked if he would release his medical records to prove his health, Paul challenged his fellow candidates to a 25-mile bike race in the Texas heat.

1. But the question does!

When moderator Wolf Blitzer returned to the question of Gingrich and Romney's finances, he asked Paul whether he felt the two candidates should return the money they had made from investments in Fannie Mae and Freddie Mac.

That subject doesn't really interest me a whole lot! the candidate quipped, to cheers and laughter from the audience. But the question does.

He was interested, he asserted, in the question of Fannie Mae and Freddie Mac themselves. Paul also pointed out that he had been advocating policies in Congress to prevent the housing crisis long before the financial bubble burst.

2. You'd better be careful.

At one point, Blitzer asked the 76-year-old congressman if he'd be willing to release his medical records to prove he could handle the strain of the presidency. Paul said he was willing, since his record is only one page, and even challenged the other candidates on stage to a 25-mile bike ride in his state.

But Paul also had a joking word of warning for Blitzer. There are laws against age discrimination, he quipped. So if you bring this up too much, you'd better be careful.

3. Overreaction and overconcern.

Paul was the only candidate on the stage to advocate opening up relations with Cuba. The Texas congressman stuck by his position, even when Rick Santorum became increasingly hawkish in opposing him.

Paul went on to argue that measures like sanctions were well-meant but counterproductive, since they only ended up hurting the people fighting unjust governments.

I worry about overreaction and overconcern, he finished. He claimed he would listen to any Latin American leader if they reached out to his government, including Cuba's Fidel Castro.

4. We should send some politicians up there.

Candidates like Santorum claimed space exploration was what made America a frontier nation, but Ron Paul wasn't convinced.

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

Paul said he would only vote for space funding for national defense purposes. We don't need a bigger and newer program, he argued. Something else deserves a lot more priority than going to the moon.

5. The freedom message

For the last question of the Florida Republican debate, the four remaining candidates were asked why they were the most likely to beat Obama. Paul pointed to  national polls that showed him doing very well against the incumbent president, and pointed to his steadfast belief in the Constitution and in his consistency as a congressman.

The freedom message in the Constitution is very appealing to everybody in all political beliefs, because it includes free markets...but it also protects civil liberties, Ron Paul said, arguing that message brings in voters from across the political spectrum.

Newt Gingrich

Gingrich was on the offensive tonight. He dismissed several of Blitzer's questions and tore into main competitor Mitt Romney for his positions on immigration and spending. The former House Speaker also  made frequent allusions to the Reagan years, and continued to attack Romney about his financial history and his lack of Capitol Hill experience throughout the night.

1. This is a nonsense question.

When Wolf Blitzer tried to get Newt Gingrich to comment on Mitt Romney's finances, and whether he felt the candidate had been transparent enough in revealing his records, the former Speaker took issue with him even asking the question.

This is a nonsense question, Gingrich said. How about if the four of us actually talk about issues that relate to governing America?

Blitzer pointed out that Gingrich himself had accused Romney of living in a world of Swiss bank accounts, but the GOP candidate deflected the point. Gingrich argued that the way he had answered in an interview was not the same as what questions he and other candidates should focus on during a debate.

2. I am also prepared to be realistic.

Gingrich continued to insist that Mitt Romney's immigration plan would mean tearing apart families and wasting money and resources. He called Romney's self-deportation plan unrealistic and limited in understanding.

I am prepared to be very tough and very bold, Gingrich said. But I am also prepared to be realistic.

3. A tiny mouse to a giant elephant.

After Romney called on Gingrich to check [his] own investments, the former Speaker charged that comparing his investments to Romney's was like comparing a tiny mouse with a giant elephant, a deliberate jab at Romney's considerable wealth.

4.In the trenches

Newt Gingrich made a point of mentioning that Michael Reagan, the adopted son of the former GOP president, had just endorsed him for 2012. I am vastly closer to Reagan [than Romney], Gingrich said, a point which the former Massachusetts governor conceded.

Gingrich claimed that when he was running against Edward Kennedy in 1994, Mitt Romney said he did not want to return to the Reagan era. Those of us who were in the trenches fighting in the 1980s, it would be nice to be recognized for what we did, he said.

5. You don't just have to be cheap everywhere.

Mitt Romney went after Newt Gingrich for what he deemed promises for reckless spending. He pointed out that the former Speaker had called for construction of a new Interstate highway in South Carolina, a new VA hospital in northern New Hampshire and widening the port of Jacksonville in Florida.

But Gingrich responded, to equal applause, that knowing local issue is an important part of being a good leader. The port of Jacksonville is going to have to be expanded, he said. I think that's an important thing for a president to know.

He went on to say that being a good leader lay not in resisting spending, but in knowing the needs of individual states. It is possible to do the right things in the right order, he said. You don't just have to be cheap everywhere.

Rick Santorum

Santorum largely stuck to a message of family and faith during the last Florida debate. His main target was Mitt Romney, whom he accused of advocating the same health care plan as Democratic president Barack Obama. But some of his biggest clashes of the night ended up being with Texas Rep. Ron Paul, as the two battled over foreign policy intervention in Latin American countries.

1. He certainly wasn't listening to my answer.

When Santorum said he would become more involved in Latin America as president, Ron Paul argued that U.S. involvement would likely makes things worse, not better.

Standing up for nations like this usually means we impose ourselves, Paul said. He claimed Santorum was advocating force as a way to get along with people.

I don't know what answer Congressman Paul was listening to, Santorum replied. But he certainly wasn't listening to my answer.

He claimed he never talked about using force in Latin America, but rather about influencing countries leaning towards socialism by other means. He argued that the U.S. has ignored countries struggling towards democracy, and had hurt their peoples' cause as a result.

2. Faith has everything to do with it.

When asked how his faith will factor into his presidency, Santorum begins by referencing the Constitution. That document is the how of America, the operator's manual.

The why of America, on the other hand, is the Declaration of Independence, which centers on God-given rights, not government-given rights.

Faith can't be separate from one's politics and actions, Santorum argued. In fact, faith has everything to do with it.

3. We've been through a lot together.

Why would each of the candidate's spouses make a great first lady? Santorum noted that his wife Karen was not in the audience. Instead, his hero was at home, taking care of their seven children.

We've been through a lot together, Santorum confessed. Losing a child, having a child with a disability...the amount of love for these special kids is just palpable in her. He went on to praise his spouse for writing the book Letters to Gabriel, claiming her story of losing her son had saved other children's lives.

4. It is the same mandate.

At one point during the Florida 2012 Republican debate, Santorum accused Romney of supporting a top-down insurance system in Massachusetts, and that so-called Romneycare was no different than Obamacare.

Your mandate is no different from Barack Obama's mandate, he said. It is the same mandate.

He also claimed that Romney required his constituents to buy insurance as a condition of breathing in Massachusetts, and pointed out that the former governor, like Obama, advocated a health plan that asked those who did not buy insurance to pay a fine.

5. The global warming hoax.

In the last moments of the GOP debate, Rick Santorum mentioned that Gingrich and Romney fell for the global warming hoax.

It is unclear how many in the audience, or those viewing the debate at home, caught the comment, but Twitter users certainly did, tweeting their reactions to the statement into the early morning.