Case closed.

Mitt Romney’s lopsided Florida victory over Newt Gingrich — a stunning 14 percentage-point margin — proved the Republican front-runner can win conservatives, triumph in debates and fight a bruising campaign that can lay an opponent to waste.

Romney’s Florida win also showed Republicans he can run the kind of national campaign that can defeat President Obama in November.

“Mr. President, you were elected to lead, you chose to follow, and now it’s time to get out of the way,” he declared at his victory party Tuesday night in Tampa.

A defiant Gingrich gave a sharply worded concession speech in Orlando, mocking Romney for singing America the Beautiful the previous day. “I’m not running to be Entertainer-in-Chief,’’ he said.

Earlier in the day, Romney said that “doing well in Florida is a pretty good indication of your prospects nationally."

That’s because Florida is more like the nation than any of the other three early states.

North Florida is the Deep South. Southwest Florida is like the Midwest. Latin America meets New York in Southeast Florida. And it all mixes together along the I-4 corridor from Tampa Bay through Central Florida.

Romney walloped Gingrich in South Florida — where he led Gingrich by at least 72,000 votes — and among Hispanics statewide, exit polls showed. He won the state’s crucial senior vote, and he carried women voters by a big margin. Romney also fought Gingrich to a statistical tie with conservative, evangelical and tea party voters.

Early results indicated he lost to Gingrich in North Florida but was handily winning everywhere else in the state that ended his presidential campaign four years ago.

“Florida is the nation’s reflecting pool,” said Alex Castellanos, a Republican consultant who worked for Romney in 2008 and George W. Bush in 2004. “It is what New York and Ellis Island used to be, the gateway to the country’s future.”

Before the first ballot was even cast on Election Day, Romney had a cushion of early votes that could have exceeded 60,000. While the other campaigns were silent in early January, Romney advertised on radio and television and aggressively called and mailed early voters, who cast more than 632,000 ballots.

With the big results in from Florida, Castellanos said, the Republican race is almost history, although Gingrich has vowed to fight all the way to the national convention in Tampa this summer.

“This race won’t end tonight, but it will be over,” Castellanos said. “Romney will have done something no other non-incumbent Republican candidate has ever done: He really only lost one of the first four contests. That’s remarkable.”

Technically, Romney lost Iowa, which initially declared him the winner —only to hand it to Rick Santorum.

But Santorum has little chance if Florida’s vote is any indication. Same with Ron Paul, who didn’t campaign in Florida so he could go to smaller states with caucuses. All the candidates lack Romney’s money and organization.

On Saturday, Nevada holds its caucus. Romney is expected to win in this state, which has a heavy population of fellow Mormons. Gingrich is already lowering expectations there.

There are also no debates until Feb. 22. Until Florida, Gingrich was viewed as the great debater. But Romney edged him in Florida’s two debates. That had an effect. The debates made a difference to two-thirds of voters, 42 percent of whom chose Romney, exit polls showed.