This course surveys the framework of domestic laws—constitutional, statutory, and regulatory—and international laws that variously authorizes and constrains the U.S. government’s pursuit of national security policies, with an emphasis on developments in this area since September 11, 2001. This broad survey course in national security law analyzes the balance between liberty and security, examining both substantive questions (how and where to strike the balance?) and institutional questions (what are the roles and powers of the president, Congress, and courts in striking that balance?). National security contexts explored include (1) the use of force abroad (including targeted killing), (2) domestic security (including state restrictions on civil liberties), (3) secrecy, (4) surveillance, and (5) investigation, prosecution, detention, and interrogation of suspected perpetrators of terrorism and atrocity crimes.