In a far away land, an American corporation harms people. It could be a physical attack. Maybe it's just property destruction. The victims, cognizant of the rampant corruption within their own judicial and political systems, turn to the U.S. for relief.
They sue in a federal court under the Alien Tort Statute. Over 200 years old, it's a brief law:
The district courts shall have original jurisdiction of any civil action by an alien for a tort only, committed in violation of the law of nations or a treaty of the United States.
So can the victims in the scenario we described above sue in the U.S.? Until today, popular federal opinion said yes.