The course explores the international law regime governing war, including the law that regulates when states may resort to force and the constraints on the conduct of warfare itself. We will begin by considering when states may permissibly use force, and how changing security threats, including terrorism, the proliferation of weapons of mass destruction, and the commission of widespread humanitarian atrocities challenge and are reshaping the legal framework on recourse to force. We will then explore the rules governing the conduct of military operations, including the constraints on the means and methods of war, the rules governing the treatment of detainees, and the protections extended to civilians and noncombatants in armed conflict. A particular focus of the class will be the application of these rules in non-traditional, asymmetric conflicts between states and terrorist and other non-state groups. Special Instructions: Any student may write a paper in lieu of the final exam with consent of instructor. After the term begins, students accepted into the course can transfer from section (01) into section (02), which meets the R requirement, with consent of the instructor. Elements Used in Grading: Class participation, written assignments, research paper or final exam.