The Florida Republican presidential primary kicked off in earnest Monday night with a quiet but tough debate.

With an audience that was asked not to applaud or cheer, the NBC debate had a more restrained feel than its raucous predecessor in South Carolina.

But that didn’t mean the candidates were restrained.

Former Massachusetts Gov. Mitt Romney harshly criticized former Speaker Newt Gingrich, saying the Georgia Republican resigned “in disgrace” and then became an “influence peddler.”

“I don’t think we can possibly retake the White House if the person who’s leading our party is the person who was working for the chief lobbyist of Freddie Mac,” Romney said.

Gingrich called the charge “misinformation” and said that he never lobbied for the government-backed mortgage company.

“I understand your technique. … It’s unfortunate, and it’s not going to work very well, because the American people see through it,” he said.

The issue of home mortgages had special resonance for the audience in Florida, where home foreclosures have been pervasive during the economic downturn.

The second half of the debate shifted to even more Florida-centered issues, including offshore drilling, immigration, space exploration and sugar subsidies.

Gingrich, Romney and former Sen. Rick Santorum (R-Pa.) advocated for strong anti-Castro policies, an issue that the sizable Cuban population in the state closely watches.

Romney got a chuckle from the audience when asked how he would respond if he got a “3 a.m. phone call” that Cuban leader Fidel Castro had died.

“First of all, you thank heavens that Fidel Castro has returned to his maker and will be sent to another land,” he said.

Gingrich got a bigger laugh by going even further.

“I guess the only thing I would suggest is I don’t think that Fidel is going to meet his maker,” Gingrich said. “I think he’s going to go to the other place.”

Rep. Ron Paul was the only candidate to argue for opening up relations with Cuba.

“I think we’re living in the dark ages when we can’t even talk to the Cuban people,” the Texas Republican said. “I think it’s not 1962 anymore. And we don’t have to use force and intimidation and overthrow of governments. I just don’t think that’s going to work.”