DES MOINES — Is Iowa for sale?

That is the perception sending shudders through the state’s Republicans, after the leader of Rick Perry’s Iowa campaign quit when Mr. Perry suspended pay to staff members, then quickly went to work for Donald J. Trump, who he had earlier said lacked a “moral center.”

The head-spinning dismount and remount came three weeks after another embarrassing episode for the state’s Republicans. A long-running scandal over under-the-table payments to a state senator to endorse Ron Paul’s presidential bid in 2011 led to the federal indictment this month of Mr. Paul’s former campaign manager.

On Tuesday, at a meeting of the Polk County Republican Party in Des Moines, the two events were linked in many conversations — as they have been all week by Iowa’s political insiders, who are hypersensitive about the state’s privileged role as the first to vote in presidential races.

Many non-Iowans resent the attention paid to the state, which will hold its caucuses Feb. 1. To deflect the doubters, party officials and the state’s ranks of paid strategists strive for an image of ethical professionalism and a level playing field for all candidates, which is now being questioned.