Republican leaders in Iowa, which holds the nation’s first nominating contest early next year, acknowledged that Ms. Palin’s celebrity bought her a lot of time — maybe even until Labor Day — but said that remaining above the fray for too long had risks…

“To be honest,” Mr. Schoenfeld said, “I have not come across a lot of folks that are waiting in the wings for Governor Palin to get in the race.”

But Peter Singleton, a self-styled Palin volunteer who has spent seven months traveling in Iowa to build support for her, said an army of workers would materialize if she gave the word.

“She has a lot more support in this state than people have any idea,” said Mr. Singleton, who said he did not work officially for Ms. Palin. “The race is wide open right now.”