Obama campaign volunteer Chris Elsenbast, of Ames, Iowa, works the phone Wednesday at the Obama campaign headquarters in Ames. Iowa's presidential caucuses are typically a gray-haired affair, but this year candidates are working to entice college students and even high school kids to show up.

Des Moines, Iowa ? Candidates in Iowa are trying to entice college students and even 17-year-old high school kids to turn out for presidential caucuses that are typically gray-haired affairs.

In the past two caucuses, nearly 65 percent of participants were older than 50. Yet John Edwards, Barack Obama and Hillary Rodham Clinton are betting that even a few new faces could sway a close contest.

They’re putting their faith in people like Chris Elsenbast, a 17-year-old high school senior in Ames, a college town just north of Des Moines. Elsenbast is head of Ames High School’s chapter of BarackStars, an organization set up by the campaign with groups throughout the state.

“I agree with a lot of his policies, but I think he is really like a different type of politician,” said Elsenbast, who will turn 18 before the caucuses and plans to support Obama.

Campaigns hope to take advantage of a quirk in Iowa’s caucus rules, which allow 17-year-olds to participate if they’ll be 18 by Election Day, Nov. 4, 2008.

Ryan McNulty, a 17-year-old whose birthday is in December, has volunteered for the Edwards campaign and plans to support him at the caucuses this winter. The high school senior in Norwalk, a suburb of Des Moines, became interested in Edwards after discussing the candidates with his government teacher.

“He’s the most genuine of all the candidates,” McNulty said. “He represents the common person better than the others.”

In seeking student support, the Obama campaign looks first for leaders whose participation could prompt others to take part.

“From the debate team to the student council to the football quarterback, we are looking for leaders,” campaign organizer Steve Hildebrand said. “There’s no question we want to find students who have influence over other students.”

Iowans in their teens and early 20s seem especially fertile ground for Obama, who has drawn huge crowds at colleges.

“The key for us is building an organization that can harness that enthusiasm and turn it into support,” spokesman Tommy Vietor said.

If history is any indication, that will be quite a chore.

In 2004, only about 17 percent of Democratic caucus-goers were younger than 30. Attending the caucuses, held in each of the state’s 1,784 precincts, can be intimidating to newcomers, unaccustomed to publicly declaring their preferences for a candidate and bargaining with others.

Still, it’s not new for candidates to seek a youthful boost, said Dennis Goldford, a political science professor at Drake University.

“There’s a history of trying to turn them out,” Goldford said. “There’s not much success in that.”

The campaigns recognize the challenge but contend that this time might be different. Considering that only a small percentage of Iowans – about 90,000 Republicans in the last contested election in 2000 and 124,000 Democrats in 2004 – take part in the caucuses, even a small bump in the number of participants can make a difference.

If the candidates succeed in altering the demographics of caucus attendees, it will be a shift of historic proportions, Goldford said.

“These are people who tend not to turn out, and the big question is can they get them to turn out,” Goldford said.