Customary International Law as U.S. Law: A Critique of the Revisionist and Intermediate Positions and a Defense of the Modern Position

In a recent referendum, the citizens of Oklahoma overwhelmingly approved a State constitutional amendment providing that the courts of the State shall not consider international law or Sharia law in rendering their decisions. The amendment\u27s exclusion of Sharia law has garnered most of the media attention, but more consequential by far is the measure\u27s directive to the State courts to disregard international law. Similar measures have been proposed in other States, some of them merely barring consideration of Sharia law or foreign law, but others barring consideration of international law as well. These measures are clearly unconstitutional insofar as they would prohibit the State courts from enforcing one of the two main forms of international law--treaties--as the U.S. Constitution by its terms requires State courts to give effect to the nation\u27s treaties, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding. But the federal Constitution does not expressly address the status of the other principal form of international law--customary international law, or the unwritten law that governs the relations among states and results from a general and consistent practice of states followed by them from a sense of legal obligation. These proposed State laws thus starkly raise the question whether the States may prohibit their courts from giving effect to the United States\u27 obligations under customary international law. This article offers a critique of the intermediate positions and, in the process, explicates and defends the modern position. Critics of the modern position often describe it as the claim that customary international law has the force of federal law always and for all purposes. But this uncompromising conception of the modern position is a phantom. Adherents of the modern position have always accepted that not all of customary international law binds foreign states or the federal Executive as a matter of U.S. domestic law. The heart of the modern position is that customary international law binds State actors and thus preempts State law applicable to State officials and private parties. The basic case for the modern position relies on an inference from the constitutional structure very similar to the one advanced by Bellia and Clark: Violations of customary international law risk retaliation against the nation as a whole. Permitting States to violate it allows States to externalize the costs of such violations, thus likely producing excessive violations. Part I explicates and offers a preliminary defense of the modern position. It sets forth the affirmative case for the modern position based on constitutional structure, original intent, and pre- and post- Erie doctrine, responding to arguments put forward in the initial wave of revisionist scholarship, but deferring to part II responses to criticisms raised by scholars advancing intermediate positions. Part I shows that the basic structural case for the modern position was well understood by the Founders. Viewed in the light most favorable to the revisionist view, the evidence of original intent and the pre-Erie cases reflect two contending positions. The first is that the Constitution itself preempts State conduct that violates the state-to-state portion of the law of nations. The other is that customary international law had the status of general common law. Before Erie, the general common law was understood as different from either federal or State law, but was closer in operation to modern-day federal law than to modern-day State law. No one claimed that customary international law had a status comparable to modern-day State law. Part II examines the intermediate positions and concludes that all but that of Bellia and Clark suffer from fundamental flaws. Ramsey\u27s concept of nonpreemptive federal law is another name for State law. Thus, Ramsey\u27s approach would replicate one of the problems that most concerned the Founders--the lack of federal judicial power to prevent or remedy violations of customary international law by the States. Young\u27s proposal to employ choice-of-law rules to determine the applicability of customary international law satisfies Erie\u27s requirement that all law applied in this country\u27s courts be either State or federal, but only because choice-of-law rules are themselves creatures of either State or federal law. To the extent that Young would relegate the applicability of customary international law to State choice-of-law rules, his proposal would present severe difficulties stemming from the indeterminacy and inappositeness of such rules, and, like Ramsey\u27s approach, would reproduce the problem that most concerned the Founders. Young\u27s approach would alleviate these problems by allowing for the use of federal choice-of-law rules in some contexts, but he emphasizes that such rules would be applicable very rarely. Aleinikoff\u27s approach would violate the one principle that all agree Erie establishes: that the substantive law applied in the State and federal courts must be the same. The intermediate position of Bradley, Goldsmith, and Moore is problematic because it would place inapposite limits on the judiciary\u27s ability to enforce customary international law as federal law. The intermediate approach proposed by Bellia and Clark is thoroughly convincing, but it is not really intermediate. Their structural argument for according preemptive force to some customary international law is basically the same as the strongest argument for the modem position. The flaw in their argument is that they do not take it far enough. Their structural argument actually provides substantial support for most of the modern position. Part III reconsiders the modem position in the light of the revisionists\u27 argument that the customary international law of today differs in important respects from the state-to-state branch of the law of nations as known to the Founders and as it existed before Erie. The revisionists\u27 concerns about the indeterminacy of customary international law and the loosening of the requirements for recognizing such law have some validity and relevance, but these concerns can be adequately addressed by restricting the range of customary norms having preemptive force to those that satisfy a heightened standard of clarity and acceptance. The revisionists\u27 concerns about the new subjects addressed by customary international law--in particular, the fact that such law now addresses how a nation treats its own citizens-does not warrant any additional restriction. The final part of the article addresses a seldom-analyzed aspect of the revisionist position--the claim that norms of customary international law that lack the force of preemptive federal law may be given the force of State law through incorporation by State legislatures or courts. The author argues that, for straightforward reasons, the States lack the power to make norms of customary international law applicable to foreign states or officials or federal officials. A State\u27s incorporation of such norms against its own officials or against private parties would pose a less obvious structural problem: because customary international law evolves through the accumulation of state practice and opinio juris, State court decisions regarding the content of such law could, in combination with the acts of other States and foreign states, eventually result in the crystallization of norms of customary international law that the federal government does not support, or the erosion of norms that the federal government does support. State court decisions regarding the content of customary international law thus interfere with the federal executive branch\u27s recognized power to speak for the United States at the international plane regarding the content of such law. This structural problem can be addressed either by denying the States the power to incorporate norms of customary international law or by recognizing the Supreme Court\u27s jurisdiction to review decisions of the State courts regarding the content of customary international law even when such law is relevant to the case only because it has been incorporated as State law. The author concludes that the latter solution is preferable and that such review would be consistent with Article III