– On the surface, Iowa's Republican presidential caucuses seem healthier than ever: Would-be candidates are flocking here mere months after the last White House race ended, drawing sizable crowds and ample news coverage. Sen. Ted Cruz of Texas and former Sen. Rick Santorum of Pennsylvania were here for a Christian conservative conference this month, and Sen. Rand Paul of Kentucky has come to the state twice since May.

But Iowa's political leaders worry that looks can be deceiving and that the prized role of the Republican caucuses is in jeopardy. Establishment Republicans fear that conservatives have become such a dominant force here that they may drive mainstream presidential candidates away.

That would relegate the caucuses to little more than a test of the party's right-wing sentiment.

"It just creates a self-selecting field," said David Kochel, a longtime Iowa Republican strategist. "The spotlight will still be here, because the Democrats are all going to show up, but with Republicans it could be optional."

New Hampshire is pegged as the more unpredictable of the two kickoff states, prone to rewarding insurgents and providing momentum for campaigns in subsequent states.

It has been Iowa in recent years, however, that propelled conservative upstarts — Mike Huckabee in 2008 and Santorum in 2012 — who ultimately failed to gain mainstream support. The party's eventual Republican nominees waged less than intense efforts in Iowa and paid no penalty.

That precedent could embolden candidates like Gov. Chris Christie of New Jersey and Sen. Marco Rubio of Florida to spend their time elsewhere and play down or even skip the state altogether.

"You're going to see conservatives probably not play as much in New Hampshire, and you're going to see moderates not play here," Santorum said in an interview this month before he addressed the gathering of Christian conservatives.

That is exactly what senior Iowa Republicans fear. And it is why some in the party are already taking steps to curb one of the more controversial elements of the caucus process: the Ames Straw Poll.

Held every summer before a contested caucus, the poll was intended to be equal parts barbecue, political revival and moneymaker for the party. But it has become a drain on the campaigns of presidential candidates, and the potential embarrassment of a poor performance offers another reason to stay away.

Party officials were especially chagrined last year after Rep. Michele Bachmann of Minnesota, having won the 2011 straw poll, finished in last place in the actual caucuses and ended her presidential campaign shortly thereafter. So now, like a Civil War doctor amputating a gangrenous leg to save the life of a patient, Gov. Terry Branstad wants to end the Ames tradition.

"I just think the major contenders are not going to want to compete in an expensive and meaningless process," Branstad said of the straw poll. "So we need to come up with something better."

Said Mike Murphy, a longtime Republican strategist: "The danger for the caucuses is that they follow the fate of the straw poll in just measuring one sector of the party."

More moderate candidates, he said, may "just let Santorum, Cruz and Bozo the Clown all fight it out."