The notion that Mr. Daniels could have been — and might still be — a unifying standard bearer lingers more in Washington Republican circles than the Tea Party-saturated Republican electorate at large, said Dave Funk, co-chairman of the Republican Party in Polk County, Iowa. Mr. Daniels is a strong voice on fiscal discipline, but he also stirred opposition by calling for a truce on social issues within the party.

Katon Dawson, a former South Carolina party chairman, said: “The Republican base has sobered up and said: ‘I’m not going to do what Washington says or what the editorial pages say. I’m going to vote for the guy who’s got my back.’ ”

But fear within the Republican establishment is rising again. “All of us want to see a coalescing behind a nominee so we can go into a debate with the incumbent president,” said Representative Eric Cantor, the House majority leader.