Taking Legal Pluralism Seriously: The Alien Tort Claims Act and the Role of International Law Before U.S. Federal Courts

The issue of pluralistic deficit in decisionmaking processes and in the judicial process covers a wide range of questions, relating pluralism to contexts both within and outside the state level. Legal pluralism, in fact, is a general phenomenon linked to the coexistence of different systems of rules, concepts, and values, which has always existed, but whose relevance has surely increased in recent decades, when multifold relationships and interactions increasingly challenge the possibility of isolating law as a merely national element.The analysis of the judicial application of the Alien Tort Claims Act (ATCA) by U.S. federal courts is a specific instance where several important issues concerning the relevance and scope of legal pluralism in the international context arise. The decision by the Supreme Court in Sosa v. Alvarez-Machain in June 2004 is an important step in a field that has been rapidly expanding in the last twenty years, after the groundbreaking decision of the Court of Appeals for the Second Circuit in Filártiga v. Peña-Irala, and can be usefully taken as a starting point for the discussion of the relevance of legal pluralism in U.S. and international law. Although the central feature of Sosa, and the line of cases decided by federal courts prior to it, is the use of the ATCA as a means to protect international human rights, its potential scope is wider because the interplay of international law with U.S. domestic law envisaged by the ATCA is not confined to a specific subject matter.