The Law of Nations and the United States Constitution offers a new lens through which anyone interested in constitutional governance in the United States should analyze the role and status of customary international law in U.S. courts. The book explains that the law of nations has not interacted with the Constitution in any single overarching way. Rather, the Constitution was designed to interact in distinct ways with each of the three traditional branches of the law of nations that existed when it was adopted--namely, the law merchant, the law of state-state relations, and the law maritime. By disaggregating how different parts of the Constitution interacted with different kinds of international law, the book provides an account of historical understandings and judicial precedent that will help judges and scholars more readily identify and resolve the constitutional questions presented by judicial use of customary international law today. Part I describes the three traditional branches of the law of nations and examines their relationship with the Constitution. Part II describes the emergence of modern customary international law in the twentieth century, considers how it differs from the traditional branches of the law of nations, and explains why its role or status in U.S. courts requires an independent, context-specific analysis of its interaction with the Constitution. Part III assesses how both modern and traditional customary international law should be understood to interact with the Constitution today.

Anthony J. Bellia Jr. is the O'Toole Professor of Constitutional Law and a Concurrent Professor of Political Science at the University of Notre Dame. He specializes in the teaching and research of constitutional law, federal courts, federalism, legal history, procedure, and contracts. He is the founding director of the Notre Dame Program on Constitutional Structure and a member of the American Law Institute (ALI). His published work includes many law review articles and the book Federalism. After receiving his J.D. from Notre Dame Law School, he clerked for Judge William M. Skretny of the United States District Court for the Western District of New York, Judge Diarmuid F. O'Scannlain of the United States Court of Appeals for the Ninth Circuit, and Associate Justice Antonin Scalia of the Supreme Court of the United States.

Bradford R. Clark is the William Cranch Research Professor of Law at George Washington University Law School. He specializes in the teaching and writing in areas of civil procedure, constitutional structure, federal courts, and foreign relations. His published scholarship includes a chapter in Pre-Emption Choice (2009) and articles in California Law Review, Columbia Law Review, Harvard Law Review, Texas Law Review, University of Chicago Law Review, University of Pennsylvania Law Review, and Virginia Law Review. He holds a JD from Columbia University School of Law, and he clerked for The Honorable Robert H. Bork of the U.S. Court of Appeals for the D.C. Circuit, and for The Honorable Antonin Scalia of the Supreme Court of the United States.