This paper identifies and analyzes two legal questions raised by the war against the al Qaeda terrorist organization. First, did the September 11, 2001 attacks initiate a war, or "international armed conflict," or was it only an act punishable under criminal law? Second, what legal rules govern the status and treatment of members of al Qaeda and the Taliban militia that harbored and supported them in Afghanistan? We argue that the United States is currently engaged in a state of armed conflict with al Qaeda, a multinational terrorist organization whose leadership declared war on the United States as early as 1996, and the Taliban militia, which harbors and supports that organization. This state of armed conflict justifies the use of military force by the United States to subdue and defeat the enemy, separate and apart from any ordinary law enforcement objectives that may also justify coercive government action against members of al Qaeda and the Taliban militia. To give legal recognition to the current armed conflict is not to confer upon members of al Qaeda or the Taliban militia the privileged status of lawful combatants. Neither group complies with the four traditional conditions of lawful combat long established under the laws of war and recognized by the Geneva Conventions. Members of al Qaeda and the Taliban militia have chosen to fight in blatant disregard for the laws of armed conflict and are, accordingly, unlawful combatants not entitled to the legal status of prisoners of war under the Geneva Conventions.