William Barr, the leading candidate to replace Jeff Sessions as U.S. Attorney General, argued three cases at the U.S. Supreme Court.

Barr, who would step in for Acting Attorney General Matthew Whitaker, would be only the second attorney general to be confirmed to the position twice.

He argued two cases while serving as General Counsel for telecommunications companies. The other, a criminal case, he argued while U.S. Attorney General during the George H.W. Bush Administration.

Barr argued on behalf of Verizon Communications, Inc. in 2001 and GTE Corporation in 1998. Both involved the Federal Communication Commission’s power to regulate monopolistic carriers.

Barr’s first high court argument came in 1992, on behalf of the federal government. Although it is unusual for the U.S. to be represented by attorneys outside of the Office of the Solicitor General, it isn’t unprecedented. Deputy Attorney General Rod Rosenstein made his high court debut last term.