In his paper "International Human Rights in American Courts," Judge Fletcher concludes that Sosa v. Alvarez-Machain “has left us with more questions than answers.” Sosa attempted to adapt certain principles belonging to the "general law" to a post-Erie positivistic conception of common law while maintaining fidelity to certain historical expectations. “[I]t would be unreasonable,” the Court thought, “to assume that the First Congress would have expected federal courts to lose all capacity to recognize enforceable international norms simply because the common law might lose some metaphysical cachet on the road to modern realism.” The Court was unwilling, however, out of concern for assuming a more expansive judicial role than the Alien Tort Statute (ATS) justified, to hold that federal courts may hear any claim for a violation of customary international law. In an effort to maintain fidelity to the First Congress's expectations, the Court held in Sosa “that federal courts should not recognize private claims under federal common law for violations of any international law norm with less definite content and acceptance among civilized nations than the historical paradigms familiar when [the ATS] was enacted” specifically, “violation of safe conducts, infringement of the rights of ambassadors, and piracy.”

I will discuss here a problem that Judge Fletcher rightly observes Sosa did not discuss–“the subject matter jurisdiction problem.” In particular, what constitutional power does Congress have to authorize federal court jurisdiction over claims based on customary international law?