Republican Debate in Arizona: LIVE COVERAGE
Former Pennsylvania Sen. Rick Santorum, former Mass. Gov. Mitt Romney, Texas Rep. Ron Paul and former House Speaker Newt Gingrich face off tonight in Arizona for their last primary debate before Super Tuesday. Click here for live coverage of the debate, hosted by CNN, with minute-by-minute updates. REUTERS

Mitt Romney, Ron Paul, New Gingrich and Rick Santorum showed no mercy during last night's GOP debate. They tackled a broad range of foreign, domestic and social issues, including immigration law, foreign intervention in Latin America, Gingrich's ties to Freddie Mac, Romney's links to Obamacare--and whose wife would make a great first lady.

Get the candidate's top quotes from the CNN-sponsored event below, and be sure to read up on our live coverage of last night's Florida 2012 Republican debate.

Mitt Romney

The former Massachusetts governor made a very strong showing last night, but those portions of the debate between himself and Newt Gingrich got very ugly, very fast. Romney went after the former House Speaker for his offbeat moon colony plan and his involvement in Fannie Mae and Freddie Mac. And when Gingrich accused Romney of being anti-immigrant and of making similar investments in Mae and Mac, 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, claiming his solutions would only exacerbate the situation. Romney, whose father is a Mexican immigrant and whose mother's family hails from England, found the epithet inexcusable.

To say that I'm anti-immigrant is repulsive, he told Gingrich. He also noted 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 minutes later 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 argued, but is it really reasonable to expect grandmothers and grandfathers would do so?

Our problem is not 11 million grandmothers, Romney shot back to some 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?

First, Romney countered, he didn't invest in those companies. They were made through a blind trust, and were part of a mutual fund. But Mr Speaker, have you checked your investments? Romney said, before saying their financial commitments, 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 costs. In Florida, it's NASA, but in South Carolina, it was an interstate highway. That's what got us into the trouble we're in now, he argued. We've got to say no to this kind of spending.

Newt Gingrich

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

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?

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

2. I am prepared to be very tough and very bold, but 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.

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 vaulted Republican 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 asserted 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, Gingrich 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 did not mean resisting spending, but 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.

Ron Paul

Ron Paul continued to be the firecracker candidate this round. He was the only candidate to advocate warming relations between the U.S. and Cuba, but also warned against overreaction and overconcern in other countries' affairs. In the realm of Fannie Mae and Freddie Mac, the Texas congressman 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 ended up challenging his fellow candidates to a 25-mile bike race.

1. But the question does!

After the first commercial break, moderator Wolf Blitzer returned to the question of Gingrich and Romney's finances once again, asking the Texas congressman 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! Paul quipped, to cheers and laughter from the audience. But the question does. He was interested in the question of Fannie Mae and Freddie Mac themselves, and 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 can handle the strain of the presidency. Paul said he was perfectly willing, since his record is only one page, and even challenged the other candidates on stage to a 25-mile bike ride in the Texas heat whenever they wanted to give it a try.

He also gave a joking word of warning to 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.

Ron Paul was the only candidate on the stage to advocate opening up relations with Cuba, but the Texas congressman stuck by his position, even when Rick Santorum became increasingly hawkish in his own position towards South and Central America.

Paul argued that measures like sanctions to punish countries the U.S. opposed were counterproductive and only ended up hurting the people fighting unjust governments.

I worry about overreaction and overconcern, he finished, saying that he would listen to any Latin American leader, if they reached out to his government.

4. We should send some politicians up there.

Though candidates like Santorum claimed space exploration was what made America a frontier nation, 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.

He continued by saying that 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 debate last night, the four remaining candidates were asked why they were the one person on this stage that is most likely to beat Barack Obama. Paul pointed out that national polls show him doing very well against Obama, and pointed to his steadfast belief in the Constitution and in political action that came from them.

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, he said, arguing that message brings in voters from across the political spectrum.

Rick Santorum

For the most part, Rick Santorum 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, arguing that he knew other ways than force 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. 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 said. Losing a child, having a child with a disability...the amount of love for these special kids is just palpable in her.

3. 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 claims God-given rights, not government-given rights.

Faith isn't separate from his politics and his action, he argues. In fact, faith has everything to do with it.

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 asserted that Romney required his constituents to buy insurance as a condition of breathing in Massachusetts, and claimed that the former governor 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 mentions 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.