President-elect Donald Trump’s pick to lead the Pentagon won’t take over for several more months, but one prominent Senate Republican is telling current Defense Secretary Ash Carter that his work leading the military is all but finished.

On Monday, Senate Armed Services Committee Chairman John McCain, R-Ariz., wrote to Carter asking him to “suspend all efforts on the development and implementation of rules and regulations at the Department of Defense that would change long-standing policy, including with regard to military personnel ratings, standards, uniforms, job titles, and related issues.”

The move is both a plea by the Senate’s top defense lawmaker for calm before the military leadership transition and a jab at Carter’s recent policy moves. He and McCain have sparred in recent months over Carter’s planned “Force of the Future” initiatives, designed to modernize military workforce rules to help with recruiting and retention.

“Many of the Department’s recent actions in this regard have been questionable and misguided,” McCain wrote. “Any effort to continue in that direction during a presidential transition and lame-duck session of Congress would be inappropriate.”