Before polls closed on Election Day, Mr. Erickson and Mr. DeMint convened a conference call to identify the next conservative battlegrounds, urging thousands of followers to direct the energy and money they had spent in the New York race toward a Rubio victory. The Club for Growth is now backing Mr. Rubio, and produced an anti-Crist ad featuring the hug.

Endorsements from conservative leaders like Mike Huckabee and Dick Armey and glowing coverage from George F. Will and National Review have made Mr. Rubio, 38, the sudden standard bearer for a more conservative Republican Party. In the past few months, he has begun pulling closer to Mr. Crist in polls and fund-raising, collecting nearly $1 million in the last cycle.

Mr. Crist, endlessly tanned, endlessly sunny, is known as a gifted campaigner with savvy for symbolism.

Hoping to emphasize his record as tough on crime when he ran for governor, he had the host of “America’s Most Wanted” deliver his papers to elections officials. He came into office promising to cut property taxes, and promoting consensus on issues like the environment and stem cell research. And if they sometimes say he is trying too hard to please everyone, voters, Democrat as well as Republican, have rewarded him with high ratings.

The National Republican Senatorial Committee backed Mr. Crist as soon as he announced he was running in May, thinking it would save trouble. He is as avid a fund-raiser as he is a campaigner, and helped deliver the state, and effectively the Republican presidential nomination, to Mr. McCain  so the party could save money in Florida to spend elsewhere.

“I think pragmatism is not a bad thing,” said the committee’s chairman, Senator John Cornyn of Texas.

But, hounded by conservative bloggers, Mr. Cornyn announced this month that he did not plan to spend any money in the primary. The committee does not usually spend in primaries; the need for such a statement spoke to the heat of the race, 10 months before primary day.