Peter Irons’s War Powers favors congressional initiative in questions of war and peace but makes a historical argument that our government has strayed from the constitutional design in the service of an imperialist foreign policy. John Yoo’s The Powers of War and Peace seeks to overthrow the traditional perspective on war powers espoused by Irons in favor of executive initiative in war. Yoo also pursues a revisionist perspective on the treaty power, which favors executive initiative in treaty negotiation and interpretation but insists on congressional implementation so as to minimize the impact of international obligations on domestic law. This Essay criticizes Irons’s approach for its failure to provide a normative defense of congressional initiative in war and takes issue with some of the historical and structural analyses underlying Yoo’s defense of executive unilateralism in the realm of war powers. Because Yoo’s arguments on the treaty power raise questions of methodological consistency, he is susceptible to the criticism that his arguments are motivated more by prudential and policy considerations than by fidelity to constitutional text, structure, and history. The Essay concludes that, while the constitutional text, structure, and history are clear and consistent and support Irons’s arguments favoring congressional war powers, the Constitution provides little guidance on how the treaty power should operate. Yoo’s view that treaties do not bind the President finds no support in constitutional text or structure. This Essay offers a structural interpretation of the constitutional treaty power different from Yoo’s that would promote U.S. participation in multilateral treaty regimes that foster security and the rule of law.