Von Nürnberg über Rom nach Kampala

International criminal law has experienced a tremendous development over the past few decades. The Nuremberg Trials laid the foundations for individual responsibility for international crimes. The greatest success in the following development is the establishment of the International Criminal Court (ICC) by the Rome Statute of 1998. Operational since 2002, the Court is to try cases of the most serious crimes of concern to the international community, namely the crime of genocide, crimes against humanity, war crimes and the crime of aggression (Art. 5 of the Statute). The exercise of jurisdiction over the latter, however, was postponed in Rome. Only after a provision was adopted defining the crime of aggression and the rules governing the jurisdiction of the Court the ICC could exercise said jurisdiction. It was only in 2010 when the Review Conference of the Rome Statute, held in Kampala, Uganda, adopted the amendments on the crime of aggression. The long and intense academic, but also political debate that preceded the Review Conference reflected the unresolved issues that led to the original postponement in 1998, especially regarding the relationship of the UN Security Council and the ICC in determining and trying cases of aggression. It was all the more surprising that in the last minute, a consensus was reached. But this consensus came with a price. The present article analyses the proposed amendments as adopted in Kampala. While undoubtedly a great achievement both the definition and the rules governing the jurisdiction suffer from some uncertainties. The definition of the crime of aggression builds on the well-established definition of an act of aggression as it appears in the relations among States. This, however, falls short of capturing the modern phenomena attached to acts of aggression, especially with regard to non-state actors. Secondly, in elaborating the Court's jurisdiction, the States at the Review Conference succeeded in guaranteeing the Court's independence. The Security Council will not act as a filter to determine which cases of aggression may appear before the Court. Meanwhile, other provisions on the jurisdiction reveal the political price that had to be paid. The position of States not party to the Rome Statute and the implementation of an opt-out mechanism for the amendments provide for potentially large exceptions to the Court's general jurisdiction. It is now the responsibly of the States, but also of the international community as a whole, to prevent that the crime of aggression remains a paper tiger.