Surveys the law of armed conflict (LOAC) and customary international law as applied by the United States in warfare. From where does LOAC arise? What is a war crime – and who decides? What is “unnecessary suffering,” and what drives that legal determination? When does LOAC apply and what role do other rules of law, such as domestic U.S. law and International Human Rights Law play in regulating the conduct of armed conflict? Does it cover non-state actors? What are U.S. LOAC obligations, and how are they enforced? How does one distinguish illegal combatants from prisoners of war? Where do military commissions come from, and who may be tried by them? Could the atomic bombing of Nagasaki have been a war crime? Can a superior’s order constitute a defense to war crime charges? What is the U.S. position in regard to laser weapons? Land mines? Non-lethal weapons? Torture? Rendition? Reprisals? The assassination of enemy commanders? What is an illegal order, and what should a soldier do if she receives one? How may battlefield war crimes be prosecuted? Our inquiry will focus on the law applicable to the conduct of U.S. military operations in past and current conflicts, whether or not they be declared, whether they be internal or international. Although primarily focused on the law of land warfare, the law of air and naval warfare, as well as space information warfare, will be considered.