Customary International Law in State Courts Julian G. Ku* TABLE OF CONTENTS I. Introduction ..................................................................................... 266II. The Founders and Customary International Law ........................... 271 A. The Problem with State Courts ........................................... 272 B. The Text of the Constitution ............................................. 273 C. Congress and the Judiciary Act of 1789 ............................. 278 D. The President and the Law of Nations ................................. 281 E. The Courts............................................................................. 286 1. Neutrality Cases .......................................................... 286 2. Diplomat Cases .......................................................... 288 F. Summary ............................................................................. 290III. State Courts and the Development of Customary International Law ............................................................................ 291 A. Immunity for Ambassadors and Public Ministers in B. Transit ................................................................................... 292 Irregular Abduction of Overseas Fugitives: The Ker Doctrine ................................................................................ 299C. Foreign Sovereign Immunity ............................................... 307 1. Marshall and Foreign Sovereign Immunity .... 308 2. Restrictive Theory of Foreign Sovereign Immunity .................................................................. 310 3. Mexico Default Cases ................................................ 313 4. Waiver ....................................................................... 315 5. Effect of Recognition ................................................. 318Associate, Debevoise & Plimpton, New York. Olin Fellow 1999-2000, University of Virginia School of Law. J.D. 1998, Yale Law School. I am grateful to the following individuals for their helpful comments on earlier drafts of this article: Lillian Bevier, Curtis Bradley, G. Edward White, Paul Stephan, John Setear and members of the Legal Theory Workshop at the University of Virginia School of Law. All mistakes and omissions, of course, remain my own.VIRGINIA JOURNAL OF INTERNATIONAL LAW [Vol. 42:1 D. 6. The Rise of Executive Lawmaking ...............................321Prohibition on Intercourse with Enemy Aliens...................... 3221. War of 1812................................................................ 3232. Civil War ................................................................... 3253 Real Property ............................................................. 3274. Life Insurance ............................................................ 328E. Summary .......................................................................................332 IV. Implications for the Modem Understandings of the Status of CIL ...............................................................................................333A. Original Intent........................................................................ 334B. Historical Role of State Courts ............................................. 335C. Practical Necessity of a Federal Court Monopoly ................ 336V. Conclusion .........................................................................................337 I. INTRODUCTION International law is part of our law, and must be ascertained and administered by the courts of justice of appropriate jurisdiction. .. .I Over the past few years, legal scholars have fiercely debated the meaning of this and other statements about the proper status of customary international law in the American legal system. While a majority of scholars support treating customary international law ("CIL") as federal common law,2 an emerging group of revisionist scholars has sharply challenged this view. These scholars argue that CIL has the status of non-federal law under Erie R.R. Co. v. Tompkins3 and that CIL is not the proper area for federal court lawmaking.4 1. The Paquete Habana, 175 U.S. 677, 700 (1900). 2. Federal common law refers to the federal law interpreted and applied by federal courts that is not specifically authorized by a congressional enactment. RESTATEMENT (THIRD) FOREIGN RELATIONS LAW OF THE UNITED STATES § I II cmt. d. (1987) [hereinafter RESTATEMENT (THIRD)] (stating consensus among scholars that customary international law is federal common law); Harold H. Koh, Is International Law Really State Law?, I I1 HARV. L. REV. 1824 (1998) (arguing that customary international law is federal law); see also Gerald L. Neuman, Sense and Nonsense About Customary International Law: A Response to Professors Bradley & Goldsmith, 66 FORDHAM L. REV. 371 (1997) (same); Beth Stephens, The Law of Our Land: Customary In-ternational Law as Federal Law after Erie, 66 FORDHAM L. REV. 393 (1997) (same); Ryan G o od m a n & D e r e k P . J i n k s , Filartiga's Firm Footing International Human Rights and Federal Common Law, 66 FORDHAM L. REV. 463 (1997) (same). 3. 304 U.S. 64 (1938). 4. See Curtis A. Bradley and Jack L. Goldsmith, Customary International Law as Fe deral Common Law: A Critique of the Modern Position, 110 HARV. L. REV. 815 (1997) (arguing that customary international law as federal common law is a "modem" view with no doctrinal or historical justification) [hereinafter Bradley and Goldsmith, Critique]. See also JOHN M. ROGERS, INTERNATIONAL LAW AND UNITED STATES LAW 115 (1999) (arguing that customary mtema-2001] CUS TOMAR Y I NTERN ATIONA L LA W 267 The outcome of this debate will have significant practical consequences. If CIL is federal common law, federal courts could use CIL to preempt inconsistent state law without any official authorization from the President or Congress.5 For instance, an individual facing the death penalty for committing a crime prior to his eighteenth birthday could challenge his death sentence on the grounds that the state statute authorizing his execution violated federal law as expressed in CIL.6 Additionally, a number of federal courts have relied on the understanding that CIL is federal common law in order to adjudicate lawsuits charging violations of international human rights law.7 If the revisionist view is accepted by the courts, some of the legal