A prominent conservative lawyer has made a private appeal to President Donald Trump not to select Judge Brett Kavanaugh to fill retiring Justice Anthony Kennedy’s vacancy on the U.S. Supreme Court, according to sources inside and outside of government.

James Bopp Jr., a veteran Supreme Court litigator from Indiana, sent a letter to Trump and Vice President Mike Pence urging the president not to pick Kavanaugh, currently on the U.S. Court of Appeals for the D.C. Circuit, said multiple sources with knowledge of the letter.