Mr. Bush is returning to Iowa on Saturday so he can attend the state Republican Party’s annual Lincoln Dinner in Des Moines, along with 10 other declared and likely presidential candidates.

It is a potentially awkward moment given that Mr. Bush, the former Florida governor, revealed on Tuesday that he would skip the Iowa Straw Poll in August — a fund-raiser for the state party — that his older brother won in 1999 on his way to the White House.

His decision was not unexpected, given that the straw poll’s younger, ideologically driven voters have the potential to deal Mr. Bush, who is crosswise with many conservatives on issues like education and immigration, an embarrassing defeat.

But Mr. Bush’s ready-made constituency in the state’s business class and political establishment is also showing signs of nervousness about his sparse presence here.

“There’s lots of angst,” said Douglas E. Gross, a fund-raiser for George W. Bush and chairman of Mitt Romney’s 2008 campaign in Iowa. “My concern is that people are writing him off very early and the chances of coming back from that are not easy.”

Mr. Gross, who was the 2002 Republican nominee for Iowa governor, said members of the party’s establishment who “should be Bush people” were lining up with other candidates. One of those he named, Robert Brownell, a supervisor of Polk County, which includes Des Moines, recently endorsed Senator Marco Rubio of Florida.