Sam Singer is a Trial Attorney with the United States Department of Justice, Civil Division, Federal Programs Branch. His work focuses primarily on defending federal statutes, regulations, and agency actions in cases involving matters of constitutional and administrative law. Mr. Singer has represented the United States in numerous cases involving constitutional and statutory challenges to national security programs, including the terrorist watchlists, U.S. arms control obligations, and the President’s authority to take military action against terrorist groups overseas. Before joining the Federal Programs Branch, Mr. Singer was an associate at Sidley Austin in Washington D.C., where his practice focused on complex commercial litigation, appellate advocacy, and international arbitration. Mr. Singer served as a law clerk for the Honorable Terrence L. O’Brien, United States Court of Appeals for the Tenth Circuit, and he served as a Staff Law Clerk for the United States Court of Appeals for the Seventh Circuit.