This essay, stimulated by themes discussed by Harold Koh and Todd Buchwald, examines the International Criminal Court (ICC) and the amendment to the 1998 Rome Statute to include the crime of aggression within the ICC’s jurisdiction. The definition adopted in Kampala in 2010 is too long to quote in full but merits careful examination. For example, it states that the “‘crime of aggression’ means the planning, preparation, initiation or execution, by a person in a position effectively to exercise control over or to direct the political or military action of a State, of an act of aggression which, by its character, gravity and scale, constitutes a manifest violation of the Charter of the United Nations.” It then adopts large swaths of UN General Assembly Resolution 3314 (XXIX) of 1974—the definition of aggression—as its own. Commentators recognized problems with the 1974 definition at the time. The post-Kampala Rome Statute purports to achieve objectivity with respect to aggression through removal of everything having to do with context and the totality of the circumstances. These matters surely should be—and must be—of central importance not only to nonparties but also to the parties to the Rome Statute. The fact that they are absent forms the raison d’être of this essay. Because the ICC is a permanent body, able to take jurisdiction of ongoing problems, its actions may have significant implications for world public order.

In this essay, I take up two concerns raised by Harold Koh and Todd Buchwald in their critique of the Kampala amendments on aggression: what they term “proxy prosecution” and the notion of aggression as a uniquely political question. I also take issue with the argument in Alain Pellet’s response on attacks by nonstate actors.

These areas of contention notwithstanding, there are important issues on which I think that Koh and Buchwald get it right. In forthcoming work, I argue that the object and purpose of the criminalization of aggression precludes an interpretation of Article 8bis of the Rome Statute that would include humanitarian interventions not authorized by the Security Council. Nonetheless, the failure to make this textually explicit at Kampala was a mistake that the authors are correct to lament. Similarly, they accurately identify the ambiguities in the provisions on the amendments’ entry into force as an entirely avoidable defect that creates unnecessary confusion. These important points notwithstanding, the article takes some misleading positions on the politics of the crime.

Having embarked in 49 BCE on his long war against Pompey, Julius Caesar reportedly commented “alea iacta est”—events have passed a point of no return. With the adoption and uptake of the Kampala amendment on the crime of aggression the Rubicon has also been crossed with twenty-six states (i.e. merely four less than the required quorum) having ratified the amendment. A significant further number of states have ratified the Rome Statute after the adoption of the Kampala amendment, posing the interesting question whether they ought to be counted towards that quorum.

At the review conference in Kampala, States Parties adopted three new provisions on the crime of aggression for inclusion in the Rome Statute, as well as consequential amendments to the Elements of Crimes. However, states parties did not consider revisions to the procedural arrangements that may be required to accommodate the crime of aggression. The crime of aggression requires a link to states, being limited to acts of aggression by one state against another state. The individuals that can be charged with the crime of aggression are persons “in a position effectively to exercise control over or to direct the political or military action of a State.” The crime is also connected to the international security framework, in particular the UN Charter. Given that aggression is intrinsically linked to state acts, it is “likely that the ICC [International Criminal Court] would need relevant states to cooperate, present evidence, and argue the case.” Yet the existing framework does not include an adequate right of participation for affected states. This contribution suggests one possible revision to provide a clearer legal basis for states to participate directly in ICC proceedings in respect of the crime of aggression.