Special Counsel Robert Mueller has recruited the Justice Department’s top criminal lawyer, Michael Dreeben, to help with the Russia investigation.

Mr. Dreeben is currently the U.S. Deputy Solicitor General and has argued before the Supreme Court more than one hundred times. He will help Mr. Mueller on a part-time basis. He earned his Juris Doctorate from Duke University School of Law.

“Michael Dreeben is to criminal law what Robert Mueller is to investigations,” said former Solicitor General, Neal Katyal to the National Law Journal. “Literally the very best. Yet another sign of how serious Mueller is about this matter,” he added. Mr. Dreeben has been arguing before the U.S. Supreme Court since 1989 for both Republican and Democratic administrations.

Justices of the Supreme Court praised Mr. Dreeben at his one-hundredth case before the body. At his one-hundredth case, Chief Justice Roberts asked Mr. Dreeben to come to the lectern.

“I distinctly recall your first argument in January of 1989. Throughout your career, you have consistently advocated positions on behalf of the United States in an exemplary manner,” said Chief Justice Roberts.

He added, “On behalf of the Court, I extend to you our appreciation for the many years of advocacy and dedicated service during your tenure in the Solicitor General’s Office and as an officer of this Court.”

Mr. Dreeben’s first case before the Supreme Court was against Justice John Roberts when he was in private practice.

He has taught at Duke University School of Law as visiting faculty and served as adjunct faculty at Georgetown Law. “Michael is the most brilliant and most knowledgeable federal criminal lawyer in America — period,” said Professor Walter Dellinger of Duke University School of Law to the Washington Post.