Powers under the Commerce Clauses

Article 1, Section 8, Clause 3 of the U.S. Constitution states that “Congress shall have power to … regulate commerce with foreign nations, and among the several states, and with the Indian tribes.” This clause is often (and usefully) understood as three distinct clauses, or grants of legislative power--the interstate commerce clause, the foreign commerce clause, and the "Indian" commerce clause. The interstate commerce clause provides the constitutional basis for innumerable federal criminal statutes (and much other federal regulatory law). The foreign commerce clause is one basis on which Congress relies for criminal statutes that are designed to apply to actors and conduct abroad, outside of U.S. territory.

The first two cases, Lopez and Taylor, address the breadth and the limits of Congress' commerce clause power. In the third case, Clark, the court addresses the constitutionality of a criminal statute that relies upon the foreign commerce clause, and the application of that statute to extraterritorial activity--i.e., conduct that occurred in another country.

Another Article I basis for federal criminal law that applies outside of U.S. territory is found in Section 8, Clause 10: “Congress shall have power to define and punish piracies and felonies committed on the high seas, and offenses against the law of nations." "The law of nations" means international law; for centuries piracy as been universally recognized as a crime under international law. "The high seas" are beyond the territory of any nation state. Clause 10 gives Congress the power to define and punish felonies in international waters, but international law--generally incorporated into U.S. domestic law, or at least for the most part respected by U.S. officials--provides separate rules that additionally govern states' authority over vessels and actors on the high seas. For example, a ship is treated as the territory of the state under which it is flagged, which means that, generally speaking, one state's law enforcement officials have no more authority to board a ship flagged to another state than they do to enter the territory of that other state without permission.