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.