Mitt Romney was first in the Florida primary by a solid margin on Tuesday night, topping rivals Newt Gingrich, Rick Santorum and Ron Paul to win his second contest of the GOP nomination fight. As Karen Tumulty reported :

Mitt Romney’s sweeping victory in the Florida Republican primary Tuesday did two things for him that he badly needed: It set the front-runner back on a glide path to the 2012 presidential nomination, and it raised his standing with the GOP’s conservative base.

Florida, the fourth state to vote this primary season, was not only the biggest prize yet, but also the purest test of where the party stands nationally.

Unlike earlier primaries in New Hampshire and South Carolina, Florida’s contest was open only to registered Republicans; about seven in 10 voters identified themselves as somewhat or very conservative, according to exit polls.

Though Romney’s victory could be a turning point, senior Republicans say the race for the nomination is far from over.

“Florida is a big and diverse state that will be a crucial state in the fall. This is an important win for Romney,” said Ralph Reed, head of the Faith and Freedom Coalition, a conservative Christian political organization. “But given all the ups and downs we’ve had, I don’t think you can call this for Romney just yet.”

The size and breadth of Romney’s win provide the first real evidence that he has the potential to coalesce a party that has been deeply split between its establishment wing, which backs him, and the insurgent forces of the tea party movement, which have been suspicious of his moderate record.

Romney showed resilience and a willingness to alter tactics after his loss in the South Carolina primary to Newt Gingrich, who surged in the polls before the Florida primary only to be beaten back in part by a more aggressive Romney in the final debates. As Philip Rucker explained:

Mitt Romney regained the upper hand in the Republican presidential race last Thursday when he and his campaign machinery focused a series of carefully orchestrated attacks on rival Newt Gingrich’s character and temperament.

The effort reflected a disciplined but more combative campaign operation that for the first time simultaneously pummeled its chief Republican rival and President Obama, while managing to keep attention on Romney as a fiscal problem-solver. Romney’s advisers said that they were pleased with how rattled Gingrich seemed to be in Florida, and that the campaign plan there would be a model for how they continue to wage battle against the former House speaker.

The contrast between the two campaigns’ approaches was most evident last Thursday.

Gingrich was in Mount Dora, addressing a rally “as a citizen,” he said, and he erupted in a tirade against Romney, calling him “some guy who has Swiss bank accounts, Cayman Islands accounts, owns shares of Goldman Sachs that forecloses on Florida, and is himself a stockholder in Fannie Mae and Freddie Mac.”

Romney was in Jacksonville, delivering a carefully scripted speech beneath a 30-foot banner that read: “OBAMA ISN’T WORKING.” Speaking from a printing plant that is closing after a century in business, the former Massachusetts governor was fiery but composed and accused the president of governing from “fantasy land.” He took no questions from the audience or reporters, instead letting his remarks drive his two main themes: fixing the economy and defeating Obama.

On television, meanwhile, Romney’s campaign and allies battered Gingrich with paid advertising. At their battle stations, Romney’s aides in concert labeled Gingrich as “unhinged” and called the former House speaker “Dr. Newt and Mr. Hyde.” Then that evening, Romney went on the attack himself, getting the better of Gingrich at the CNN debate, and the momentum was his.

The Fix analyzed the five lessons that the Florida primary taught us. As Chris Cillizza wrote:

After sorting through the exit polling, listening to the candidates’ speeches and sifting through the county-by-county results, we came up with five major lessons learned. (And, yes, we always learn lessons in fives. Doesn’t everyone?)

Here they are:

1. Negative ads work: Ninety-two percent of all the television ads run in the Florida Republican presidential primary were negative, according to an analysis by Elizabeth Wilner of the Campaign Media Analysis Group (CMAG).

Romney and his team decided after his South Carolina loss that they were going to release the hounds and they did just that in Florida, dropping a barrage of negative ads ($15 million and counting ) that cast Gingrich as an ethically challenged and unreliable candidate.

While Gingrich decried the onslaught and tried to make it the issue in the race, voters didn’t perceive Romney as overly negative. Thirty four percent said Romney had run an unfair campaign while an equal 34 percent said the same of Gingrich, according to exit polling.

The lesson in Florida is the same lesson we learn in race after race (after race): Voters say they don’t like negative ads but the messages those negative commercials carry often heavily influence the voting choices they make.

And that means that there are plenty more negative commercials to come as the race moves to Nevada, Colorado, Maine, Arizona and Michigan.

2. Romney can win Republicans: After his crushing defeat in South Carolina, questions were — rightly raised — about Romney’s ability to win self-identified Republican voters. He did much to answer those questions in Florida.

Eighty percent of voters in the Florida primary identified themselves as Republicans; Romney took 48 percent among that group to 33 percent for Gingrich.

(Sidebar: The only people who can vote in the Florida Republican primary are registered Republicans and yet 18 percent said they were independents and two percent said they were Democrats, according to exit polling. Odd.)

Two-thirds of Florida voters said they supported the tea party; Romney took 41 percent to Gingrich’s 37 percent among that group.

There are still signs of vulnerability for Romney on the far ideological right of the party, however. Among those who described themselves “very conservative”, Romney took 30 percent to 42 percent for Gingrich. And among those who strongly support the tea party, Gingrich won 45 percent to 33 percent for Romney.

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