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As part of a symposium on Justice Stephen Breyer’s book, “The Court and the World,” this essay describes and defends a particular role for the Supreme Court in the area of foreign relations law, which is to act as a filter between international law and the American constitutional system. In such a role, the Court does not act as an impermeable barrier to international law but rather ensures that when international law passes into the U.S. legal system, it does so in a manner consistent with the structure and values of the constitutional system. This filtering role is appropriate, the essay contends, because international law is generated through processes that often make it ill-suited for direct application in the U.S. legal system, and because international law is frequently designed to perform functions different from the ones demanded of domestic law. Using a number of the cases discussed in Justice Breyer’s book, the essay provides examples of the Supreme Court’s filtering role in four scenarios: First, the intersection of treaties and individual constitutional rights; second, the relationship between the treaty power and American federalism; third, delegations of authority to international institutions; and fourth, the domestic application of customary international law.

Library of Congress Subject Headings

International law, International and municipal law, Supreme Court, Constitutional law