"Crime is ordinarily proscribed, tried, and punished according to the laws of the place where it occurs. American criminal law applies beyond the geographical confines of the United States, however, under certain limited circumstances. State prosecution for overseas misconduct is limited almost exclusively to multi-jurisdictional crimes, that is, crimes where some elements of the offense are committed within the state and others are committed beyond its boundaries. A surprising number of federal criminal statutes have extraterritorial application, but prosecutions have been few. This may be because when extraterritorial criminal jurisdiction does exist, practical and legal complications, and sometimes diplomatic considerations, may counsel against its exercise."
CRS Report for Congress, 94-166