Statutory interpretation presumptions

Although sometimes Congress expressly states that a statute is intended to apply extraterritorially, often it does not, which can require courts to interpret statutes to determine whether the statute properly applies to conduct outside of U.S. territory. United States v. Bowman is a seminal case on when and how courts apply the presumption against extraterritorial application; that presumption is now summarized in Restatement (4th) § 404:

Courts in the United States interpret federal statutory provisions to apply only within the territorial jurisdiction of the United States unless there is a clear indication of congressional intent to the contrary.

The next case, United States v. Bowman, provides the standard, still-much-cited account of this presumption.

See also § 406: Interpretation Consistent with International Law
Where fairly possible, courts in the United States construe federal statutes to avoid conflict with international law governing jurisdiction to prescribe. If a federal statute cannot be so construed, the federal statute is controlling as a matter of federal law.

When defendants challenge the charges against them as an impermissible extraterritorial application of a statute, sometimes the answer turns not whether the statute has extraterritorial reach but whether the offense is in fact one that involves extraterritorial application; that is not always obvious even when defendants are outside the U.S. at the time they commit a crime. Pasquantino and Hussain are examples.