TAMPA, FLA. — Mitt Romney routed Newt Gingrich in the Florida primary Tuesday night, rebounding smartly from an earlier defeat and taking a major step toward the Republican presidential nomination. Gingrich vowed to press on despite the one-sided setback

Romney, talking unity like a nominee, said he was ready to take the Republican helm and “lead this party and our nation.” In remarks to cheering supporters, the former Massachusetts governor unleashed a strong attack on Democratic President Barack Obama and said the competitive fight for the GOP nomination “does not divide us, it prepares us” for the fall campaign.

“Mr. President, you were elected to lead, you chose to follow, and now it’s time to get out of the way,” he declared.

Returns from 98 percent of Florida’s precincts showed Romney with 46 percent of the vote to 32 percent for Gingrich, the former House speaker.

Former Pennsylvania Sen. Rick Santorum had 13 percent, and Texas Rep. Ron Paul 7 percent. Neither mounted a substantial effort in the state.

For the first time in the campaign, exit polls showed a gender gap, and it worked to Romney’s advantage.

He was leading Gingrich 52-28 among women voters and was winning men by a far smaller margin of 41-36.

Ominously for the thrice-married Gingrich, only about half of women voters said they had a favorable view of him as a person, compared to about eight in 10 for Romney.

Nor was Romney’s victory a narrow one. His winning percentage approached 50 percent and a majority that would demolish Gingrich’s oft-stated contention that the voters who oppose Romney outnumber those who favor him.

Still, the former speaker said, “We’re going to contest everyplace and we are going to win.”

As in Iowa, New Hampshire and South Carolina, about half of Florida primary voters said the most important factor for them was backing a candidate who could defeat Obama in November, according to exit poll results conducted for The Associated Press and the television networks.

Not surprisingly, in a state with an unemployment rate hovering around 10 percent, about two-thirds of voters said the economy was their top issue. Nearly nine in 10 said they were falling behind or just keeping up. And half said that home foreclosures have been a major problem in their communities.

The winner-take-all primary was worth 50 Republican National Convention delegates, by far the most of any primary state so far. That gave Romney a total of 87, to 26 for Gingrich, 14 for Santorum and four for Paul, with 1,144 required to clinch the nomination.

But the bigger prize was precious political momentum in the race to pick an opponent for Obama in a nation struggling to recover from the deepest recession in decades.

That belonged to Romney when he captured the New Hampshire primary three weeks ago, then swung stunningly to Gingrich when he countered with a South Carolina upset 11 days later.

Now it was back with the former Massachusetts governor, after a 10-day comeback marked by a change to more aggressive tactics, coupled with an efficient use of an overwhelming financial advantage to batter Gingrich in television commercials.

Gingrich brushed aside any talk of quitting the race.

“We are going to contest everyplace,” he said, standing in front of a sign that read “46 states to go.”

“It is now clear that this will be a two-person race between the conservative leader, Newt Gingrich, and the Massachusetts moderate,” he said.

Santorum disagreed, and said so. In Nevada, where he was campaigning for the state’s caucuses on Saturday, he said, “Newt Gingrich had his chance, had his shot, had a big boost and win out in South Carolina and couldn’t hold it.” He said the voters are “looking for a different conservative and alternative to Mitt Romney now.”

Romney won the Nevada caucuses four years ago and is favored to repeat his triumph this Saturday. Caucuses in Colorado, Minnesota and Maine follow, with primaries in Wisconsin on Feb. 21 and in Michigan and Arizona at the end of the month.