The Law of Nations as Constitutional Law

Abstract

Courts and scholars continue to debate the status of customary international law in U.S. courts, but have paid insufficient attention to the role that such law plays in interpreting and upholding several specific provisions of the Constitution. The modern position argues that courts should treat customary international law as federal common law. The revisionist position contends that customary international law applies only to the extent that positive federal or state law has adopted it. Neither approach adequately takes account of the Constitution’s allocation of powers to the federal political branches in Articles I and II or the effect of these powers on judicial precedent applying the law of nations throughout U.S. history. Several specific powers — such as the powers to send and receive ambassadors, declare war, issue letters of marque and reprisal, and make rules governing captures — can only be understood by reference to background principles of the law of nations. At the time of the Founding, it was reasonably assumed that U.S. courts would recognize the traditional rights of foreign sovereigns under the law of nations as a means of respecting the Constitution’s allocation of specific foreign relations powers to the political branches. Considered in this light, the Supreme Court’s decisions applying traditional principles derived from the law of nations throughout U.S. history have largely — if not exclusively — served to implement this allocation of powers. From this perspective, both the modern and the revisionist positions rest partly on erroneous premises. The modern position errs in claiming that the best way to read Supreme Court precedent applying the law of nations is that federal courts have independent Article III power to adopt such law as federal common law. Consistent with the original public meaning of the Constitution, this precedent is better read to apply certain traditional principles of the law of nations when necessary to uphold the political branches’ recognition, war, reprisal, and capture powers under Articles I and II. The revisionist position overlooks the role of these powers by requiring the political branches or states to adopt traditional principles of the law of nations before courts may apply them. Historical understandings and judicial practice suggest that courts must apply traditional principles of the law of nations not only when the federal political branches or the states have adopted them, but also when Articles I and II require courts to do so. In such instances, the law of nations functions as constitutional law.

Keywords: constitution, law of nations, customary international law, federal courts, Article I, Article II, Article III, recognition, treaty, ambassador, war, reprisal, capture, federal common law, foreign relations, charming betsy, brown, nereide, schooner exchange, paquete habana, belmont, pink, sabbatino

JEL Classification: K19, K33