Of course, Mr. Bush’s campaign is just getting going in Iowa; one Bush strategist said it would enlist elements of the old guard before long. But it is unclear how many, if called, would rally behind Mr. Bush.

“He’s at a different point in history than his brother George was,” said George W. Wittgraf, a lawyer in Cherokee, Iowa, who was state chairman for the first President Bush. “People were looking for an alternative to Bill Clinton then. While they’re looking for an alternative to Barack Obama, there are lots of other potential candidates.”

Ralph R. Brown, who worked for both earlier Bush candidacies in the state, said Mr. Bush was wise to seek out a fresh team in Iowa. “There will be a new generation,” he said. “That’s what it takes to win.”

Although Mr. Bush has said he wants to be his “own man,” he is inescapably in his family’s shadow. “We’re tired of the same old same old,” said Kellie Paschke, a lawyer in Waukee and a Republican activist in Dallas County west of Des Moines. Mr. Bush’s “name is something he’s going to have to overcome,” she said. “He is going to have to be more articulate with his fresh ideas.”

On Friday, Mr. Bush plans to meet privately with potential volunteers and staff at Jethro’s, a barbecue restaurant in Waukee. On Saturday he will appear with a dozen other 2016 hopefuls at an agriculture forum in Des Moines, then attend a meet-and-greet at a Pizza Ranch restaurant in Cedar Rapids — the city where George W. Bush first publicly declared his ambition to reach the White House, in 1999.

Jeb Bush’s own memories of Iowa include some that are less rosy. On the night of the statewide caucus in 1988, he spoke in Council Bluffs in support of his father, who ended up losing the precinct on his way to finishing third in the state (although he won the nomination and the presidency). “It was a humbling experience” for the 34-year-old Jeb, said Douglas E. Gross, a Bush family friend. “He trudges back to the Holiday Inn Express by himself like he doesn’t have a friend in the world.”

Polls show stiff resistance to Mr. Bush so far in Iowa. More than one in four likely Republican caucusgoers said they would “definitely not support Bush,” a Quinnipiac University poll found last week. Forty percent had an unfavorable opinion of Mr. Bush, with 41 percent favorable — the worst ratio of any potential candidate except Gov. Chris Christie of New Jersey.