This article provides a critical assessment of the corpus of law that the adjudicating bodies of the World Trade Organization (WTO)—the Appellate Body (AB) and panels—have used since the organization was established on January 1, 1995. After presenting a taxonomy of WTO law, I move to discern, and to provide a critical assessment of, the philosophy of the WTO adjudicating bodies, when called to interpret it. In discussing the law that WTO adjudicating bodies have used, I distinguish between sources of WTO law and interpretative elements. This distinction will be explicated in part I below. Part II provides a taxonomy of the sources of WTO law, and part III a taxonomy of the interpretative elements used to illuminate those sources. Part IV concludes.

The last decade has witnessed a rebirth of popular and academic interest in the international norms governing expropriation. Debate has centered on the competing claims of corporations, host states, nongovernmental organizations (NGOs), and other actors over the extent to which governments may regulate their economies in a manner that affects foreign investment without compensating investors for resulting economic harm. The current controversy over regulatory takings represents the second act in international law’s expropriation battles; whereas the first act comprised the long dispute between North and South over compensation after an overt nationalization, today’s dispute turns on whether a governmental regulation is an expropriation in the first place. This issue is not new to international law, as old diplomatic intercourse and arbitrations demonstrate; but the range of actors making claims, the venues for their resolution, and the outcomes of these processes are more diverse, particular attention having been generated by the case law of arbitrations under the North American Free Trade Agreement (NAFTA) and bilateral investment treaties (BITs). Complaints have concerned both the outcomes of disputes and the processes involved in their resolution.

Much of the scholarly attention given to the U.S. Supreme Court’s March 2008 decision in Medellín v. Texas has focused on the Court’s supposed ruling as to the presumptive nonself-execution of international agreements entered into by the United States, and the power of the president to implement such agreements without an act of Congress. Less heed has been paid to the impact and implications of the Court’s reasoning and analysis in interpreting the four international agreements at issue in the case: the 1945 United Nations Charter and Statute of the International Court of Justice, and the 1963 Vienna Convention on Consular Relations and its Optional Protocol. Although the Court’s analysis of the self-execution questions is beyond the scope of my contribution to this Agora, I acknowledge that the jurisprudence of treaty interpretation fits uncomfortably with the calculus of an international agreement’s selfexecution into U.S. law. And while it may seem obscure to view the Medellín decision through the lens of treaty interpretation, that is what truly brings its importance into focus, so that its impact may ultimately be seen as clarifying the established norms of U.S. foreign relations law, particularly in the selection of appropriate sources for treaty construction and the deference to be granted to various foreign relations actors and institutions.

Ever since the Supreme Court’s 1829 decision in Foster v. Neilson, it has been settled that some treaties ratified by the United States are “non-self-executing” and thus are not enforceable in U.S. courts unless implemented by Congress. Despite its pedigree, both the theory behind the self-execution doctrine and its mechanics have long befuddled courts and commentators. There is significant uncertainty, for example, concerning the materials that are relevant to the self-execution analysis, whose intent should count in determining self-executing status, the proper presumption that should be applied with respect to self-execution, and the domestic legal status of a non-self-executing treaty.

Although “[tjreaties are the law of the land, and a rule of decision in all courts,” the president and the courts may sometimes be powerless to achieve compliance with a U.S. treaty. That was the puzzling outcome of Medellin v. Texas. Even though the Supreme Court declared that the United States has an international obligation to comply with the Avena judgment of the International Court of Justice (ICJ), the Court invalidated the president’s memorandum directing Texas and other errant states to comply.

Medellín v. Texas is the first case in which the Supreme Court has denied a treaty-based claim solely on the ground that the treaty relied upon was non-self-executing. In Foster v. Neilson, the only other case in which the Court had denied relief on this ground, the Court offered its view that the treaty was non-self-executing as an alternative ground for denying relief. The Court soon thereafter disavowed its conclusion that the treaty involved in Foster was non-selfexecuting, and, in the intervening years, it repeatedly declined invitations to deny relief on this or related grounds. Many observers (including me) thought that the Court would again skirt a ruling on non-self-execution in Medellín because the president had issued a memorandum ordering compliance with the judgment of the International Court of Justice (ICJ) in Avena. After all, the Court in American Insurance Ass’n v. Garamendi had recently struck down a California law on the ground that it conflicted with a “policy” reflected in certain sole executive agreements. The president in Medellín seemed to be standing on stronger ground, as he was insisting that state law give way to an obligation imposed by a treaty that had received the consent of the Senate and was accordingly the supreme law of the land. But the Court defied this expectation, with potentially regrettable results for the law of treaties.