The adoption of the ICC (International Criminal Court) Statute in July 2002 was widely recognised as an achievement of great historic significance. Article 5 of the Statute includes aggression in the subject-matter jurisdiction of the Court. However, the crime is not yet operational insofar as its elements and jurisdictional parameters have not been defined. The ICC judges can therefore not hear aggression charges at this stage. There is a multilateral process underway in the context of the ICC to define the international crime of aggression. This process represents a culmination of efforts going back to the late 1940s to reach agreement among states on a clear basis in international law for individual criminal responsibility for acts of aggression. If the negotiations on aggression taking place within the context of the ICC Assembly of States Parties were to yield conclusive results in time, the review conference on the ICC Statute in 2009 would represent the first opportunity to make the crime of aggression operational through statutory amendments.
Although it is noteworthy that individual authors of acts of aggression enjoy impunity under international law in the 21st century, it is unclear whether such agreement will be reached by 2009. Views differ sharply among states as to whether it is desirable to have an operational international crime of aggression and, if so, how it should be defined. Some states have consistently pressed for an early and effective criminalisation of aggression. Other states are reluctant to support the criminalisation of acts of aggression, or they would not be prepared to go along with a definition unless the ICC can only take action against acts of aggression when the UN Security Council so agrees. Given the human suffering, development setbacks and poverty caused by armed conflicts, it is important to openly and thoroughly articulate and analyse all relevant arguments for and against criminalization of aggression. This research project considers some of the key obstacles in the negotiations to define an international crime of aggression.