HUTCHINSON, Kan. — In his 40 years living in Kansas, Konrad Hastings cannot remember voting for a Democrat. He is the type who agonizes over big purchases, trying to save as much money as possible. He is against stricter gun laws, opposes abortion in most cases and prefers less government involvement in his life.

But when he casts his ballot for governor in November, he plans to shun the leader of this state’s conservative movement, the Republican incumbent, Sam Brownback, and vote for the Democratic challenger.

“He’s leading Kansas down,” said Mr. Hastings, 68, who said he voted for Mr. Brownback four years ago, when he easily won his first term. “We’re going to be bankrupt in two or three years if we keep going his way.”

Voters like Mr. Hastings are at the heart of Mr. Brownback’s surprising fight for political survival.