Terrorism according to the STL's Interlocutory Decision on the Applicable Law : a defining moment or a moment of defining?

On 16 February 2011, the Appeals Chamber of the Special Tribunal for Lebanon (STL) handed down its unanimous Interlocutory Decision on the Applicable Law in response to a number of questions put to them by the Pre-Trial Judge. The decision touched on multiple legal issues arising from the court's unique jurisdictional attributes, including its jurisdiction ratione materiae over the crime of terrorism. This paper provides a commentary on two specific terrorism-related aspects of the decision: (i) the court's finding that terrorism has crystallized to form a distinct international crime under customary international law and (ii) its (re)interpretation of terrorism under Lebanese law (Article 314 of the Lebanese Criminal Code). In so doing, it draws attention to the Appeals Chamber's unique approach to customary international law formation in light of prima facie differences in state practice and the implications of a fully fledged international crime of terrorism that includes a 'transnational' element. In addition, it highlights the Appeals Chamber's internationalist interpretative approach to domestic law but also questions whether the STL should be deferential to the decisions and interpretations of Lebanese courts given its unique characteristics which do not exist in any other international court. Due to its far-reaching implications, the decision merits the attention of scholars and practitioners alike as it has the potential to affect both domestic and international approaches to, and prosecution of, terrorism for many years to come.