Jurisdiction…cannot be exercised by a State outside its territory except by virtue of a permissive rule derived from international custom or from a convention. It does not, however, follow that international law prohibits a State from exercising jurisdiction in its own territory, in respect of any case which relates to acts which have taken place abroad, and in which it cannot rely on some permissive rule of international law. Such a view would only be tenable if international law contained a general prohibition to States to extend the application of their law and the jurisdiction of their courts to persons, property and acts outside their territory, and if, as exception to this general prohibition, it allowed States to do so in certain specific cases. But this is certainly not the case under international law as it stands at present. Far from laying down a general prohibition to the effect that States may not extend the application of their laws and the jurisdiction of their courts to persons, property and acts outside their territory, it leaves them in this respect a wide measure of discretion which is only limited in certain cases by prohibitive rules.
El caso Lotus de 1927. Tribunal Permanente de Justicia Internacional