The Supreme Court held that although Cuba possessed de jure sovereignty over Guantánamo Bay, the USA exercised effective sovereignty and this alone sufficed to trigger the jurisdiction of US courts. The jurisdiction of US courts was, moreover, strengthened by the fact that Cuban courts do not themselves possess jurisdiction.

Belgium issued a law in 1993 which vested its courts with jurisdiction to entertain criminal suits on the basis of the universality principle. Consequently, a Belgian prosecutor indicted the then incumbent Congolese foreign minister for a series of international crimes, including crimes against humanity. In response, his country lodged a suit before the ICJ, arguing that the indictment violated the privilege of immunity enjoyed by foreign ministers. The validity of this argument was accepted by the Court. Universal jurisdiction was ultimately not the main issue in the case, but was discussed at length in a separate opinion to the judgment.

There is no rule of international law that prohibits the exercise of universality by national courts. There is, however, inconsistent State practice as to whether it is required that the accused is actually in the hands of the prosecuting State at the exact moment of prosecution. It is accepted that the accused need not be in the hands of the prosecuting State and his or her presence may just as well be sought by means of extradition. What is absolutely prohibited is the exercise of criminal jurisdiction on the territory of another State without its consent.

A French and a Turkish ship collided on the high seas, resulting in the death of the Turkish ship’s crew. The Turkish authorities proceeded to arrest the captain of the French ship and prosecuted him for manslaughter. The French authorities intervened and brought legal action against Turkey before the Permanent Court of International Justice, arguing that collisions on the high seas attract flag State jurisdiction only.

The Court assimilated the Turkish ship with Turkish territory and from there it was not a great leap to claim that the offence occurred on Turkish territory. This part of the judgment is bad law, given that the LOSC makes it clear that high-seas collisions attract only flag State jurisdiction. The case is best known for the claim that States may exercise any form of jurisdiction, as long as it is not prohibited by any rule of treaty or customary international law.

Yunis, a Lebanese national, was involved in the hijacking of a Jordanian airliner, which carried, among others, two American nationals. Under the guise of a drugs deal, US secret agents lured Yunis to international waters off Cyprus and arrested him. The accused argued that the USA had for a long time resisted the application of the passive personality principle and thus claimed that its courts did not enjoy jurisdiction.

Although passive personality jurisdiction is controversial, it is wholly legitimate and, in any event, the Hostages Convention includes it among its acceptable forms of jurisdiction. This type of jurisdiction is increasingly accepted when applied to terrorist and other organized attacks on a State’s nationals by reason of their nationality.