This Tuesday the Supreme Court will hear arguments in two cases that should interest every U.S. company doing business overseas, and especially those operating in the developing world. Kiobel v. Royal Dutch Petroleum Co. and Mohamed v. Palestinian Authority raise the issue of whether corporations can be sued for violations of international law under U.S. statutes, including the Alien Tort Statute. The ATS was adopted in 1789 by the first U.S. Congress. The statute permits suits by aliens in federal courts for certain alleged international-law violations, but it was moribund for nearly 200 years and its purpose remains opaque. The...