Philip Bobbitt is the Herbert Wechsler Professor of Jurisprudence and Director of the Center on National Security at Columbia Law School and Distinguished Senior Lecturer at the University of Texas. He is a Fellow of the American Academy of Arts & Sciences and a former trustee of Princeton University. He has served in all three branches of government, during seven administrations, most recently as a member of the External Advisory Board of the CIA. He has published ten books, chiefly on U.S. constitutional law, nuclear strategy, and the history and evolution of the State. His most recent work is Impeachment: A Handbook (with Black, New Edition) (2018).