Sen. Tim Kaine (D-Va.) raised concerns that Pentagon leadership changes, including the removal of a senior U.S. Army commander, may reflect personal grievances and could weaken independent military advice to the government.

Army Leadership Shake-Up Raises Questions

On Sunday, speaking on "Face the Nation," Kaine said the sudden exit of U.S. Army Europe commander Gen. Chris Donahue surprised lawmakers and raised unanswered questions inside Congress.

Donahue, widely respected on both sides of the aisle, has been ordered to submit retirement papers and is set to relinquish command on July 2, followed by his NATO role on July 9.

Kaine said lawmakers have yet to receive clear explanations from the Pentagon. "A lot of questions and very few answers," he said, adding that the situation "caught us all by surprise."