In recent years there has been a significant expansion of the number and kinds of cases in U.S. courts raising issues of customary international law. U.S. courts are increasingly asked to enforce international norms of behavior against foreign governments, state and local governments, and indeed the U.S. Government itself. To a greater and greater extent the courts themselves have become actors on the international scene: in the view of one party to a lawsuit, judicial or quasi-judicial acts may threaten to violate international law, while in the view of another party those same sorts of acts can contribute affirmatively to the development and enforcement of international law norms.
International Law | Law
Lori F. Damrosch,
Application of Customary International Law by U.S. Domestic Tribunals,
Am. Soc'y Int'l L. Proc.
Available at: https://scholarship.law.columbia.edu/faculty_scholarship/4123