Mr. Grassley told voters on Friday that he was unsure if he would vote for the Senate Republican bill in its current form, according to The Des Moines Register. “I don’t even know if we’re going to get a bill up,” said Mr. Grassley, an expert on health policy and taxes who has been in Congress for more than 40 years.

In small counties, rural hospitals and other health care providers are often the largest employers, and after years of railing against Mr. Obama’s law, Republican senators are now grappling with the impact of its possible demise.

“I am a product of rural Kansas,” Senator Jerry Moran, Republican of Kansas, told constituents this week. “I understand the value of a hospital in your community, of a physician in your town, of a pharmacy on Main Street.”