Our goal here is to address two questions raised by this Symposium that go to the heart of the status of the law of nations under the Constitution. The first question is whether the Constitution adopted the law of nations (or some subset of it) as the supreme law of the land. This fundamental question has profound implications for the proper role and status of customary international law in the U.S. federal system. The second question is whether the Constitution’s allocation of certain powers to the political branches of the federal government has any bearing on the power or obligation of federal courts to apply the law of nations. Resolution of this question is particularly important if one concludes, as we do, that the Constitution did not adopt the law of nations itself as supreme federal law. The recognition power—along with other foreign relations and war powers that the Constitution allocates to the political branches—can only be understood by reference to background principles of the law of nations. In various cases over time, the Supreme Court has upheld the Constitution’s allocation of these powers by respecting the rights of foreign nations under the law of nations.