A more thorough explanation:

The Alien Tort Statute (ATS) is a law in the United States that allows foreign citizens to sue in U.S. courts for violations of international law. The law gives federal courts the power to hear cases where an alien (a non-U.S. citizen) claims that they were harmed by a violation of international law or a treaty of the United States.

For example, if a foreign citizen is tortured or killed by a U.S. corporation or government official in another country, they may be able to sue in a U.S. court under the ATS.

However, the Supreme Court has limited the scope of the ATS in recent years. In Kiobel v. Royal Dutch Petroleum Co., the Court ruled that the ATS only applies to violations of international law that occur within the United States. In Jesner v. Arab Bank, PLC, the Court held that the ATS cannot be used to sue foreign corporations. And in Nestlé USA, Inc. v. Doe, the Court ruled that there must be a connection between a corporation's domestic conduct and the alleged violation of international law for the ATS to apply.

Despite these limitations, the ATS remains an important tool for holding individuals and corporations accountable for human rights abuses and other violations of international law.