Abstract: Is international law “irrelevant” to constitutional interpretation in the United States? How could that be? The arguments for categorical ignorance of international law in constitutional adjudication play on exaggerated fears: fear of foreign domination, fear of judicial activism, fear of the unknown. The claim of irrelevance depends on a false dichotomy between excluding international law from judicial consideration and allowing foreign institutions to control constitutional meaning. The more sensible inquiry would ask how international law has informed constitutional interpretation in the past, and how it should be used in the future.