This contribution is dedicated to Professor John Dugard. It discusses the most difficult issue to be resolved in the negotiations on the crime of aggression: the role of the Security Council in the exercise of jurisdiction over this crime by the International Criminal Court. The International Law Commission suggested a solution in the 1990s, but failing the required support and in the absence of subsequent agreement the 1998 Rome Conference could only prospectively give the Court jurisdiction over the crime of aggression. The post-Rome negotiations are characterized by, on the one hand, support from the five permanent members of the Security Council for the thesis that it should be exclusively for the Security Council to determine whether or not an act of aggression has been committed (as a precondition for the exercise of jurisdiction by the ICC) and, on the other hand, a rejection of this thesis combined with a search for alternatives by many other states. According to the analysis below, in relation to cases involving the crime of aggression the preferred way for the ICC to proceed is to exercise jurisdiction over this crime after a determination of state aggression has been made by the Security Council. Nevertheless, the view according to which such a determination could exclusively be made by the Council is rejected, on the basis of the rules of the Charter, the practice of the Security Council and the General Assembly, and decisions of the International Court of Justice. Finally, an alternative arrangement is suggested for the cases in which the Security Council is prevented from acting because of the use of the veto or because of lack of support from its members.