Senate Judiciary Chairman Charles E. Grassley is warning President Donald Trump against removing Attorney General Jeff Sessions or Special Counsel Robert S. Mueller III.

The Iowa Republican’s defense of Sessions, who faced criticism for recusing himself from the investigation of Russian interference in the 2016 presidential election, seemed in part because Grassley thinks his committee may be facing the prospect of a Supreme Court nomination later in 2018.

“I think Jeff Sessions is doing a good job even though on some issues I very dramatically disagree with him,” the Iowa Republican said on the Fox Business Network. “We’ve got three Cabinet people to approve now. We may even have a Supreme Court Justice to approve down the road a few months. The president shouldn’t be overburdening Congress with finding a new attorney general and going through that, particularly when the Democrats on every nomination [that] comes up, they filibuster.”

Some Senate Republicans have made mention of the possibility that Associate Justice Anthony Kennedy could be planning to retire this summer.

Grassley criticized the slow pace of confirmations, which has been the focus of Majority Leader Mitch McConnell of Kentucky on the Senate floor this week.