Story highlights Romney to get Secret Service protection, a source tells CNN

Mitt Romney gets Florida's 50 convention delegates, the biggest primary haul so far

Tuesday's winner will get the GOP nomination, predicts Florida Sen. Rubio

Gingrich's momentum dropped as Romney went on the offensive

Mitt Romney headed west Wednesday to begin campaigning in Minnesota and Nevada after cementing his status as the front-runner for the Republican presidential nomination with a solid victory in Florida's bitterly contested primary.

Romney had 46% compared to 32% for Newt Gingrich, 13% for former Pennsylvania Sen. Rick Santorum and 7% for Texas Rep. Ron Paul, according to the Florida Department of State website.

The victory gave Romney all 50 of Florida's convention delegates, and more importantly, new momentum heading into a series of caucuses and primaries building up to Super Tuesday on March 6, when 10 states will hold nominating contests.

In a sign of Romney's new prominence, a federal law enforcement source told CNN that Romney will receive Secret Service protection "within days."

Appearing to cheers of "Mitt, Mitt, Mitt" just 30 minutes after the last polls closed, the former Massachusetts governor thanked his supporters for what he called a "great victory."

A Florida campaign of vicious personal attacks between Romney and Gingrich, his closest competitor, raised questions about whether the process would damage the eventual winner when it comes time to run against President Barack Obama in November.

"A competitive primary does not divide us, it prepares us, and we will win," Romney said to cheers.

Reflecting the bitter campaign, Gingrich refrained from congratulating Romney when he later spoke to supporters holding signs that read "46 states to go" in reference to the early stage of the GOP nominating process.

Instead, the former House speaker tried to frame the Florida result as a narrowing of the field, saying it was "now clear this will be a two-person race between the conservative leader Newt Gingrich and the Massachusetts moderate."

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Santorum said Tuesday night that the Florida result showed Gingrich was unable to build on his previous victory, and conservatives were coalescing around Santorum's candidacy as the viable right-wing alternative to the more moderate Romney.

"Newt Gingrich had his opportunity. He came out of the state of South Carolina, he came out with a big win and a lot of money. He said, 'I'm going to be the conservative alternative. I'm going to be the anti-Mitt'," Santorum said. "It didn't work. He became the issue. We can't allow our nominee to be the issue in the campaign."

Santorum also told CNN his campaign raised almost $4.5 million in January in what he called a fundraising surge.

Paul, meanwhile, said he was focusing on upcoming caucuses in Maine and other states where his enthusiastic support base can generate more convention delegates. So far, he noted, he was in third place in delegates, adding "that's what really counts, and we've only just gotten started."

No candidate so far has more than 10% of the 1,144 delegates needed to win the nomination at the August convention.

According to exit poll information, Romney led in most categories in Florida to show his appeal to Republican voters who said their main concern was choosing a candidate who can defeat Obama.

Romney gained significant ground in the Latino community, carrying Hispanics by 23 points. In the 2008 Florida primary, Romney lost Hispanics to eventual GOP nominee Sen. John McCain by 40 points.

In particular, Romney carried Cuban-Americans -- a vital constituency for Republicans in Florida against Obama -- by 24 points.

He lost to Gingrich only among the most hardcore elements of the GOP base -- voters who described themselves as very conservative and evangelical or born-again. However, Romney ran strongly among women voters, getting 51% to 29% for Gingrich, indicating that Gingrich's history of three marriages, two divorces and infidelity might be harming him.

Final polls closed at 8 p.m. ET and Romney jumped out to a strong early lead, buoyed by solid support among more than 632,000 voters who cast absentee or early ballots. His double-digit victory blunted any momentum Gingrich gained from his January 21 victory in South Carolina, the previous primary.

Both Romney and Gingrich focused their speeches Tuesday night on the ultimate goal -- taking on Obama in November.

Romney listed what he called the differing ideologies between himself and the president, promising to balance the budget without raising taxes and saying "together we will build an America where hope is a new job with a paycheck, not a faded word on an old bumper sticker."

"The path I lay out is not one paved with ever increasing government checks and cradle-to-grave assurance government will always be the solution," Romney said. "If this election is a bidding war for who can promise the most goodies and the most benefits, I'm not your president. You have that president today."

Gingrich pledged to compete in every contest in the nomination process, and to repeal Obama policies hated by conservatives -- such as health care reform and Wall Street reform -- on his first day in office.

"This is the most important election of your lifetime," Gingrich said, adding: "If Barack Obama gets re-elected, it will be a disaster for the United States of America. You can't imagine how radical he'll be in a second term."

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Analysts and observers said a Romney victory Tuesday would be important and could be decisive.

"I think the winner of Florida is in all likelihood going to be the nominee of our party," Florida Republican Sen. Marco Rubio told CNN Tuesday . "Florida is a mini America."

GOP strategist and CNN contributor Alex Castellanos said a Romney victory would not automatically end the Repubican nomination campaign.

"With a win, Romney puts the nomination firmly in his grip. But it appears Gingrich and Santorum will keep trying to rip it from his hand," said Castellanos, who was a Romney media adviser in 2008 but is not taking sides this year.

Gingrich stormed into Florida 10 days earlier on a roll off of his double-digit victory over Romney and the rest of the field in the South Carolina primary.

His momentum quickly faded after Romney's campaign went on the offensive, turning in two strong debate performances in the Sunshine State and unleashing a barrage of ads targeting Gingrich.

Negative ads accounted for 92% of political ads airing in Florida over the last week -- a record rate for political campaigns , according to the Campaign Media Analysis Group, which tracks advertising content and spending.

"I spent much of my academic career telling reporters, 'Relax, this is not the most negative campaign ever,' " CMAG President Ken Goldstein said. "Well, this IS the most negative campaign ever."

Romney told reporters Tuesday that he had learned his lesson from his South Carolina loss.

"If you're attacked, I'm not going to just sit back," he told reporters in Tampa, repeating a refrain he's used regularly recently. "I'm going to fight back and fight back hard."

On the day before the primary, Gingrich accused Romney of dishonesty but conceded the wave of attack ads had been effective.

"Frankly if all that stuff were true I wouldn't vote for myself," Gingrich said in Jacksonville Monday , referring to what he called "dishonest" Romney ads.

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He later told a crowd in Pensacola that "we will only win if the American people decide that they are sick and tired of the New York and Washington establishment thinking that we are dumb enough to let them try to buy an election by telling us things that we all know are just plain not true."

The Romney campaign and an independent super PAC supporting his bid have greatly outspent Gingrich and pro-Gingrich super PACs on ad buys in Florida.

Gingrich "has been flailing around a bit trying to go after me for one thing or the other," Romney said later Monday to a crowd in Dunedin. "You just watch it and shake your head. It has been kind of painfully revealing to watch."

While Romney and Gingrich were in Florida on Tuesday night to watch election returns, Santorum and Paul, knowing they're out of the running for the 50 delegates, have moved on to the next contests.

Santorum campaigned in Colorado and Nevada on Tuesday, while Paul was in Maine over the weekend and was spending Tuesday in Colorado and Nevada.

Nevada's caucuses take place Saturday, when Maine starts its week-long caucuses.

Minnesota and Colorado hold their caucuses on February 7, the same day that Missouri holds its non-binding primary.

In Lone Tree, Colorado, Santorum called on voters to consider questions that have arisen about the character and discipline of Gingrich, his main rival for support from conservatives.

"It's an issue of trust," Santorum said when a man at his Tuesday event challenged the character of Gingrich, who has been divorced twice and cited for a violation of House ethics rules.

Personal mistakes don't automatically disqualify someone from seeking high office, Santorum said, noting Gingrich has sought forgiveness.

"I don't question his sincerity of his repentance, but as I have said many times there is two areas that are open for concern and that is -- the issue of trust and whether someone who has a record of that is someone you feel comfortable has truly changed and you forgive them," Santorum continued. "That doesn't mean they necessarily have changed their ways."

The Paul and Santorum campaigns are strategically looking to states in which they can pick up delegates.

"Ultimately they're conceding in advance in Florida, while trying to shore up future states," said Doug Heye, a GOP strategist and Republican National Committee communications director. "Unfortunately for Paul and Santorum, that generally has not been a winning strategy. It's not being done out of a position of strength."

Romney's convincing win in Florida, coupled with an unfriendly calendar for Gingrich in February with friendlier Super Tuesday states more than a month away, could put Gingrich in a bind.

"February doesn't look good for Newt Gingrich. He'll lose Nevada, with its large LDS (Mormon) population and lose Michigan (February 28), where Romney's father was governor. Newt will have a long march across the desert with no debates to revive his campaign," Castellanos said.

"Newt has to hold his breath all the way to Super Tuesday, March 6th, raise 30 or 40 million dollars for advertising and fix his problem with female voters to catch Romney. Those are grandiose problems, even for Gingrich."