Updating Extraterritoriality argues that a global economy requires extraterritorial reach, and that nations have been too timid in restraining themselves from condemning international cartels on grounds of indirectness of effects. The article poses five sets of real- life fact problems, analyzes what is or is not a legitimate outreach of national law, and proposes that, in cases of world consensus principles, notably hard core cartels, the national and world interest in a global economy free of restraints of competition (the world commons of competition) should be a factor in deciding whether jurisdiction lies. The article examines how to reflect world welfare more cautiously in other cases.