After Sosa: The Future of Customary International Law in the United States

Abstract

This paper explores the role of customary international law in the U.S. legal system after the Supreme Court's decision in Sosa v. Alvarez-Machain. After discussing Sosa's impact both on alien tort litigation and on the debate over whether customary international law is federal common law, I apply Sosa's methodology to some of the open questions concerning the place of customary international law in our constitutional scheme. With respect to Article II's 'Take Care' Clause, I argue that the original understanding was that customary international law bound the President and that modern arguments for abandoning that understanding are not convincing. With respect to Article III, I argue that customary international law was originally understood to be part of the 'Laws of the United States' for purposes of Article III arising - under jurisdiction, and that there are good reasons to adhere to that position today. And with respect to the Supremacy Clause of Article VI, I argue that customary international law should today bind the states, subject to congressional override, even though this was probably not the original understanding.

Keywords: Sosa, Alien Tort Statute, customary international law