He is favored in Nevada, where there are 28 Republican National Convention delegates at stake. And, alone among the contenders, he appears to have the money to compete aggressively in all the other states as well.
Gingrich decamped from Florida but with prospects considerably dimmer than Romney's.
He was conceding nothing. Routed on Tuesday, the former House speaker vowed to stay in the race until the party convention this summer. And his decision not to call the primary winner with congratulations drew notice.
"I guess Speaker Gingrich doesn't have our phone number," Romney said.
The Florida campaign was marked by millions of dollars in negative ads, and Gingrich's promise to remain in the race raised the prospect of a months-long struggle. House Speaker John A. Boehner said he was not concerned.
"I would remind people that President Obama and Secretary of State Hillary Clinton had a fight that went through June of 2008," he said. "I think everybody just needs to realize that this will resolve itself."
Jubilant in victory Tuesday night, Romney was thrown onto the defensive the day after. "I'm not concerned about the very poor," because they have a social safety net, he said on CNN. Criticized quickly, he hastened to clarify.
"No, no, no, no, no, no, no," Romney told reporters on his campaign plane when asked about the comments. He referred back to his complete remarks, in which he had said he would focus on middle-income Americans rather than the very poor, who get government help, or the very rich, who don't need it. "My energy is going to be devoted to helping middle-income people," he said.
By then, though, he was drawing criticism from conservatives who worried he was showing a penchant for verbal gaffes as well as from Obama's campaign manager. "So much for 'we're all in this together,' " tweeted Jim Messina.
