President Bill Clinton frequently has engaged in unilateral acts of executive war making in defiance of the war clause of the Constitution, which vests in Congress the exclusive authority to initiate hostilities on behalf of the American people. Recently, Clinton ordered in concert with NATO allies a massive air and missile assault against the Federal Republic of Yugoslavia, an attack that ranks as the most intensive and sustained military campaign conducted by the United States since the Vietnam War. This article analyses the administration's legal and constitutional justifications, and concludes that Clinton's action violates the fundamental requirement of the war clause—authorization of hostilities by both houses of Congress. Clinton's “presidential war” against Yugoslavia marks the first time in our history that a president has waged war in the face of a direct congressional refusal to authority the war. The war clause, it appears, has become a dead letter.