Ambassador John J. Sullivan, a former U.S. Deputy secretary of state and former U.S. ambassador to the Russian Federation, is a partner in Mayer Brown’s DC and New York offices. He co-leads the National Security practice, established eight years ago, prior to his most recent stint in government service. Ambassador Sullivan has a distinguished career in private practice and public service, where he has served under five Presidents of both parties. Prior to his most recent position, he served in a variety of roles, including Deputy Secretary and General Counsel of the Commerce Department and Deputy General Counsel of the Defense Department. He has also served in the Office of Legal Counsel at DOJ, and clerked for Justice Souter on the Supreme Court.