Mr. Rubio spends less and less time trying to tap into the discontent that has been at the forefront of the midterm elections. A wiser course for Republicans, he said, is offering an alternative, not simply being the angry opposition.

“The solution isn’t just to paralyze government,” Mr. Rubio said in an interview as he traveled the state last week from here in the Panhandle to Miami. “Vote for us because you couldn’t possibly vote for them? That’s not enough. It may win some seats, but it won’t take you where you want to be.”

His course bears little resemblance to those of other insurgent candidates, many of whom hope to ride a combative streak  and little else  to Washington. Mr. Rubio is increasingly trying to turn his candidacy into one built more on ideas than outrage, which is why he delivered three detailed speeches in the past week alone on education, veterans’ affairs and retiree issues.

The strategy is partly born out of necessity for a wonky candidate trying to compete for attention in what has become a preprimary spectacle in Florida, where Mike Tyson was the best man in the wedding of Jeff Greene, a billionaire developer seeking to become the Democratic Senate nominee, and a multimillionaire, Rick Scott, is running for governor as a Republican.

Mr. Rubio, 39, a former speaker of the Florida House, won an ideological victory of sorts in pushing Mr. Crist from the Republican Party, but in electoral terms, Mr. Rubio has struggled to overtake the governor in the Senate race. The outcome of the Democratic primary between Representative Kendrick B. Meek and Mr. Greene will define the three-way fall campaign and give voters choices across the political spectrum.