Customary International Law in United States Courts

Abstract

Over the past two decades, the status of customary international law in U.S. courts has been the subject of vigorous debate. On the one hand, proponents of the "modernist" position contend that rules of customary international law are presumptively rules of federal law, which apply directly in U.S. courts and preempt inconsistent state law even in the absence of federal legislative or executive authorization. On the other hand, the "revisionists" argue that, in the absence of congressional legislation or a U.S. treaty, rules of customary international law are generally not matters of federal law, and will therefore generally be governed by state law. This Article argues for an approach that rejects central elements of both the modernist and revisionist positions, while also adopting other aspects of both positions. The Article contends that the text, structure, and objectives of the Constitution, and the weight of judicial authority, require treating all rules of customary international law as rules of federal law, but that such rules will be directly applicable in U.S. courts only when the federal political branches have expressly or impliedly provided for judicial application of a particular rule. This approach would mirror the way in which courts apply U.S. treaties and other international agreements—treating them as matters of federal law but applying their provisions in U.S. courts only to the extent authorized by the political branches. The intentions of the political branches regarding application of particular rules of customary international law by U.S. courts can be deduced from a number of indicia, analogous to those applied to determine whether particular treaty provisions are self-executing; these include the content and character of the relevant rule of international law, statements by the Executive or Legislative branch, and the content, character, and historical treatment of related rules of international law. The position proposed in this Article produces materially different results from either ...