But Gingrich’s message changed in Florida from day-to-day as Romney stayed more focused on his “Obama isn’t working” slogan. Gingrich was unexpectedly scolded by Sen. Marco Rubio for calling Romney “anti immigrant.”

Not only was Gingrich thrown off message last week, Rubio also vouched for Romney’s conservative bona fides along with former Gov. Jeb Bush, beloved in Florida Republican circles. Neither Rubio nor Bush endorsed any candidate.

Gingrich’s level of frustration was underscored Tuesday when his campaign began robo-calling voters to suggest that Romney was against “religious freedom” and “Holocaust survivors” because in 2003 in Massachusetts he vetoed money for kosher food for nursing homes.

Gingrich, who had complained he had been “carpet-bombed” by Romney’s camp, on Tuesday initially refused to say whether he approved the phone message. He later disavowed any knowledge of it.

But for all of Gingrich’s complaining, about 34 percent of Republican voters saw his campaign as negative — only 3 percentage points less than Romney, exit polls showed.

At a precinct at the Pompano Beach Civic Center, some Republican voters preferred Romney because they described him as having less baggage than Gingrich.

“I decided walking in — that’s how undecided I was between Romney and Gingrich," said Ronald Perkins, a 60-year-old who works as a chaplain at Port Everglades. "I’m very upset by all the negative campaigning.’’

At the Belen Jesuit campus in West Miami-Dade, a Republican stronghold with about three times more registered Republicans than Democrats, Roger Cardenas, 41, voted for Romney.

“I don’t know if he can do everything he says he’ll do but he’s the only guy who can run against Obama,” said Cardenas, an electrician who came to South Florida from Cuba.

‘HAVE TO RESPOND’

Earlier in the day, Romney brushed off questions about the depth of the negative campaigning.

“When attacked, you have to respond,’’ he said.

That was the answer of a frontrunner, one who had the money and power to eviscerate his opponent. In doing so, Romney showed he was as tough as Gingrich, whose performance as a brawler captured hearts in South Carolina.

Unlike South Carolina and the other early vote states, Florida’s primary is decided by Republicans only. Although Florida is the ultimate swing state, its Republican politics are conservative.

Before Florida, Romney could be called a “Republican in Name Only” by critics on the right.

Now, with Florida under his belt, he’s almost the Republican nominee.

McClatchy Washington Bureau staff writers Lesley Clark, William Douglas and David Lightman contributed to this report. The Miami Herald’s Latoya Burgess, Marc Caputo, Howard Cohen, Lidia Dinkova, Glenn Garvin, Margaux Herrera, Alysha Khan, Alexa Lopez, Patricia Mazzei and Christina Veiga also contributed, as well as the Sun Sentinel.