The threat or use of force is prohibited by customary international law and the UN Charter when it is part of a preventive war waged against the territory of any State. In the "Lotus" case, the Permanent Court of International Justice decided, "the first and foremost restriction imposed by international law upon a State is that – failing the existence of a permissive rule to the contrary – it may not exercise its power in any form in the territory of another State." The "Caroline" test was recognized and endorsed by the Nuremberg Tribunal, who adopted the same words used in the test in judging Germany's invasion of Norway and Denmark during World War II.