Kentucky Gov. Andy Beshear, a rising national figure in the Democratic Party, is calling on the state’s Republican Sen. Mitch McConnell to either prove that he is fit to continue serving after his lengthy hospital stay or resign from office.

Beshear made the demand in a letter after McConnell’s office said Monday that the 84-year-old senator had not yet been medically cleared to leave the rehabilitation facility where he has been undergoing physical therapy. The office said he would miss a major Kentucky political event and upcoming Senate votes. McConnell was hospitalized June 14 and disclosed weeks later that it was the result of a fall.

Beshear, who is widely viewed as a potential presidential candidate in 2028, first urged McConnell in early July to release more information about his condition after weeks of public silence. His letter Tuesday marked a significant escalation.

“I am calling on you to directly and verbally address the people of Kentucky and provide proof of your capacity to serve, or resign,” Beshear wrote to McConnell.

Beshear also sent a letter to Senate Majority Leader John Thune, urging him to investigate McConnell’s condition if the senator does not demonstrate that he is capable of continuing to serve.