Some Republicans found their doubts ripening overnight. In an interview earlier in the week, Representative Peter T. King, a Republican from Long Island, said that Mr. Paladino “may be reading the public mood better than anyone.” But in a follow-up interview on Thursday, Mr. King expressed concern about Mr. Paladino’s behavior.

“I’m always skeptical and concerned when a candidate goes into his opponent’s personal life,” Mr. King said, declining to elaborate.

Mr. Paladino’s broader challenge echoes those of other Tea Party insurgents around the country, as passionate but untested candidates have toppled more-established Republicans in primaries only to struggle under the bright lights and scrutiny of general election campaigns…

“His candidacy is a manifestation of a very real anger that exists in many parts of the state,” said John J. Faso, the Republican candidate for governor in 2006. “The risk for him is that when he’s being introduced and creating a first impression in the minds of voters, especially downstate, he’s got to be able to make a positive impression while still maintaining that edge he has.”’