The process of norm evolution and development in international law has been highly debated in recent international law and international relations scholarship. However, the debate focuses primarily on states or non-state actors as the agents responsible for shaping international law. In contrast, the role of the judiciary is often neglected in the debate.1 It is an open secret, though, that courts are not merely Montesquieu’s bouche de la loi, impartial arbiters, who apply and interpret exogenous norms. Armin von Bogdandy and Ingo Venzke have already pointed out that decisions for concrete cases can hardly be derived from abstract legal concepts by the mere exercise of logical deduction.2 Instead, the application of legal provisions often involves the development of the applied norm itself. This not only applies in the domestic setting, but is also valid in the international arena.