This chapter discusses whether the war on al Qaeda and terrorism generally is part of an armed conflict or better addressed through law enforcement mechanisms. It then dissects the laws of war (jus ad bellum) regarding self-defense, host state consent, and UN Security Council authorization, and the laws in war (jus in bello) standards on drones as a weapon system, distinction between civilian and combatant, military necessity and signature strikes, proportionality, responsibility, and due process. It also introduces suggestions that human rights norms or domestic law bind state behavior regarding targeted killing. Ultimately, strikes against some non-state actors in noncombat zones fall afoul of international law, though the U.S. government argues that targeted killing with drones fully complies with all applicable laws.