This article seeks to give an impression of the way in which domestic courts are contributing to the development of international criminal law. Have they predominantly followed the case law of international tribunals and, by doing so, have they corroborated those standards? Or have they rather ventured in new directions and, as a consequence, been involved in a creative process, establishing and refining international criminal law?
Four different approaches, reflecting the position of domestic courts vis à vis the standards and case law of international criminal tribunals, are identified and analysed: strict compliance, antagonism, judicial construction, and ‘casuistry’. The author concludes that the most important contribution of domestic courts to the development of international criminal law consists of further interpretation of open-ended norms. While this is obviously inherent in the process of ‘judicial creativity’, the feature is reinforced by the non-hierarchical nature of international criminal law. As a consequence, international criminal tribunals lack the power and authority to impose their interpretation of international criminal law on domestic courts. The risk of fragmentation is mitigated, however, by the nature of criminal law, which requires strict and clear standards, and by the increasing interactions between courts at different levels.