Extraterritoriality refers to the application of a nation’s law to persons, conduct, or property outside its own territory. Customary international law allows nations to regulate extraterritorially on a number of different bases, including effects, nationality, and universal jurisdiction. Nations generally limit the extraterritorial application of their laws to a greater extent than customary international law requires. For example, the United States applies a presumption against extraterritoriality to federal law and sometimes imposes additional limitations as a matter of prescriptive comity. Some U.S. states have their own presumptions against extraterritoriality, which may differ from the federal presumption.
A Primer on Extraterritoriality
[Updated September 1, 2025] Extraterritoriality refers to the application of a state’s law beyond the state’s borders. Although the word “extraterritorial” often has negative connotations, international law permits a great deal of extraterritorial regulation. In a world where trade, information, crime, and lots of other things regularly cross borders, states often have an interest in…
Continue ReadingThe Extraterritorial Authority of U.S. States
There is one sentence in Fuld v. PLO (2025) that has always bothered me: that “The Constitution confers upon the Federal Government—and it alone—both nationwide and extraterritorial authority.” This statement is demonstrably wrong, so much so that I was easily convinced by colleagues that it did not need direct refutation. And yet that sentence has…
Continue ReadingOral Argument Recap: Suncor v. Boulder
On Monday, the Supreme Court opened its new Term with oral arguments in Suncor v. County Commissioners of Boulder County (for background on the case, check out our preview post). Justice Alito did not participate as he has recused himself. Here are some takeaways as we await the Court’s decision. No One Is Buying the…
Continue ReadingOT26 Opens with Climate Case
When the Supreme Court opens its new Term next Monday, it will hear oral arguments in Suncor Energy Inc. v. County Commissioners of Boulder County, a case in which the city and county of Boulder are attempting to hold oil and gas companies responsible under state tort law for local harms caused by climate change….
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