The political branches and the law of nations.

• Author: Bellia, Anthony J., Jr.
• Position: Re-Examining Customary International Law and the Federal Courts

INTRODUCTION

In the late eighteenth and early nineteenth centuries, the U.S. Supreme Court went out of its way to follow background rules of the law of nations, particularly the law of state-state relations. As we have recently argued, (1) the Court followed the law of nations not because it believed such law qualified as "the supreme Law of the Land," (2) but because adherence to such law preserved the constitutional prerogatives of the political branches to conduct foreign relations and decide momentous questions of war and peace. (3) Had the judiciary taken it upon itself to depart from well-established principles of the law of nations, it would have usurped the authority of Congress and the President to decide whether, when, and how to depart from such law in the conduct of foreign relations. Although we focused primarily on the extent to which the Constitution obligated courts to follow the law of nations in the early republic, the explanation we offered also rested on an important, but largely overlooked, predicate--that is, "that the political branches were free to make law in derogation of the law of nations, and that such law would bind courts as the supreme law of the land." (4) Because decisions regarding when and whether to adhere to--or depart from--the law of nations "are rather questions of policy than of law," (5) the Constitution's allocation of powers assigned such decisions to the political branches of the federal government. (6) In other words, courts generally followed the law of nations in the early republic not as a form of supreme federal law in itself, but as a means of preserving the political branches' exclusive constitutional prerogatives to decide whether, when, and how to depart from such law.

Scholars have long debated whether courts should uphold actions by the political branches that depart from the law of nations. In addition, some distinguish between congressional and executive action in this regard. Most scholars agree that courts must uphold acts of Congress that depart from the law of nations. The most prominent advocate of this position is Louis Henkin. "In principle," he claimed, "every state has the power--I do not say the right--to violate international law and obligation and to suffer the consequences." (7) Indeed, in his view, the Constitution recognizes a "national prerogative to violate international law." (8) "If Congress enacts legislation that is inconsistent with, and causes the United States to violate, an established principle of customary law, the Executive and the courts are obliged to give effect to the act of Congress." (9) In other words, "Congress, in legislating under its constitutional powers, can enact law inconsistent with an international agreement or other international obligation of the United States, thereby causing the United States to be in violation of that agreement or obligation." (10)

A few scholars, however, have asserted that courts should enforce established rules of customary international law to restrict congressional action. Jordan Paust, for instance, has argued that "well into the 20th Century no one expected that the President or Congress could even authorize a violation of customary international law and nothing in the text or structure of the Constitution permits such a result." (11) Jules Lobel has claimed that "fundamental" rules of customary international law are judicially enforceable against acts of Congress (12): "those rules of international law that reflect the fundamental norms of contemporary society bind Congress ... domestically as well as internationally." (13)

Scholars have also debated whether customary international law limits the powers of the President. Several scholars have concluded that it does not, albeit for somewhat different reasons. Some have argued that customary international law is not judicially enforceable against the President because it does not have the status of federal law. (14) Others have argued that, as a functional matter, customary international law is an ineffective constraint on executive action. (15)

In contrast, several scholars have argued that customary international law is judicially enforceable against the President. Their general claim is that customary international law qualifies as the law of the United States; thus, the President is bound to follow it under the Article II duty to "take care that the laws be faithfully executed." (16) Even so, scholars have recognized limited circumstances in which the Executive may violate customary international law without judicial reproach. First, Professor Henkin has argued that the President may disregard customary international law if the President is "acting within his constitutional authority" (17) to (1) make law in the United States (18) or (2) modify or terminate a principle of international law. (19) "The question," as Henkin describes it, is whether the President "has constitutional authority to do the act that ... superseded the customary principle." (20) Second, numerous scholars have argued that the President may violate customary international law when enforcing an act of Congress that itself deviates from such law. (21) This claim of course presupposes that Congress's power to deviate from customary international law is not subject to judicially enforceable limitations, and that the President's duty to take care that acts of Congress be faithfully executed encompasses statutes that depart from the law of nations.

Different conceptions of the role of customary international law in our constitutional system partially explain disagreement over the extent to which such law binds Congress and the President. If one believes that the Constitution somehow incorporates customary international law in its entirety--as superior to enacted statutes of the United States--then such law presumably binds Congress and the President to the same extent as the Constitution itself. (22) Or, if one believes that the Constitution authorizes judges to incorporate customary international law as federal common law, then such law may bind the President, absent congressional override. (23) Finally, if one believes that customary international law has no domestic effect unless and until adopted by the political branches, then such law imposes no judicially enforceable constraint on either Congress or the President. (24)

There is, however, a largely overlooked alternative to these three accounts that derives from the Constitution's allocation of powers and that better explains the Supreme Court's selective application of the law of nations since the Founding. This account maintains that courts historically followed the law of nations in order to preserve the constitutional prerogatives of the political branches to conduct foreign relations and to decide questions of war and peace on behalf of the nation. At the time the Constitution was adopted, the law of nations recognized a set of "perfect rights" enjoyed by all nations. These included the rights to exercise territorial sovereignty, conduct diplomatic relations, exercise neutral rights, and peaceably enjoy liberty. (25) These perfect rights were considered so fundamental that interference with any of them provided just cause for war. (26) Thus, respect for these rights was essential to maintaining peace among nations. As we have previously explained, federal courts upheld the perfect rights of nations as a means of avoiding war and preserving the constitutional prerogatives of the political branches to conduct foreign relations. (27) Accordingly, the Court has long held that any decision to depart from traditional law of nations principles--and thus risk war with another country--rests with the political branches, not the courts.

Although this account explains why the Constitution often required courts to follow the law of nations in the early republic, it also explains why the Constitution--through certain express clauses--arguably gave Congress more latitude than the President to depart from the law of nations. The Constitution vests Congress--rather than the President--with the express powers to declare war, to raise and support armies, and to provide and maintain a navy. When the Court has invoked the law of nations as a limit on executive wartime power, it has done so in order to uphold its conception of the constitutional allocation of authority between Congress and the President to decide whether and when the United States should risk starting or escalating a war by taking action that might violate the perfect rights of foreign nations. By requiring executive wartime authority to conform to the law of nations, the Court has respected congressional power to declare and determine the scope of war on behalf of the nation. It should come as no surprise, therefore, that as the Court has gradually recognized shared congressional and presidential powers over both war and foreign relations, it has also recognized some executive discretion to depart from the law of nations.

Part I describes the Constitution's allocation of foreign relations and war powers to Congress and the President. Part II explains how the Supreme Court, from the early days of the republic into the twentieth century, has applied certain principles of the law of nations as a means of respecting the constitutional prerogatives of the political branches to conduct foreign relations. Had courts departed from such principles, they would have given other nations just cause for retaliating against the United States, and thereby usurped political branch authority to determine momentous questions of war and peace. Part III explains how Supreme Court decisions applying the law of nations necessarily presupposed that the political branches may depart from the law of nations in the exercise of their respective constitutional powers. Although we do not attempt to provide a full account of the respective powers of the political...