The crowded field of candidates includes Reps. David Jolly and Ron DeSantis, businessman Carlos Beruff, entrepreneur Todd Wilcox and the state’s lieutenant governor, Carlos Lopez-Cantera. But all of the candidates have their vulnerabilities, plus there are fears that they won’t be able to raise the kind of cash necessary to run a viable campaign in one of the most expensive states in the country.

“It’s the Republican nightmare nobody wants to talk about,” said Josh Holmes, a former chief of staff to Senate Majority Leader Mitch McConnell. “Everyone knew it would be next to impossible to replace Marco Rubio, but I don’t think anyone appreciated how steep that drop-off actually is in Florida.”

Republicans believe that the candidate favored by the Democratic establishment, Rep. Patrick Murphy, is flawed and can be beaten — especially as Murphy himself is locked in a bitter primary fight with progressive firebrand Alan Grayson.