Crime of Aggression Negotiations Blocked by France, the United Kingdom, and Canada

[Professor Jennifer Trahan is director of the Concentration in International Law & Human Rights at the NYU Center for Global Affairs and convenor of The Global Institute for the Prevention of Aggression]

A Special Session of the Assembly of States Parties to the International Criminal Court (ICC) took place at the United Nations from July 7-9, 2025. At issue was whether to harmonize the jurisdiction of the ICC over all four of its crimes. At present, the crime of aggression is subject to a restrictive jurisdictional regime, so restrictive that the ICC has been unable to investigate or prosecute the crime in any situation. (For background, see GIPA Q&A.) Yet, after Russia’s full-scale invasion of Ukraine as well as aggression elsewhere, interest in seeing the crime investigated and prosecuted—given the estimated over one million casualties in that situation—has grown considerably.

The Special Session was the culmination of six months of efforts by states this spring in drafting a proposed amendment text and accompanying resolution that would harmonize jurisdiction (see report by the Working Group on Amendments). A series of regional meetings were also held in Johannesburg, Glion, Brasilia, São Paulo, Seoul, Accra, and Berlin. The draft resolution proposed by states was in large part identical to one proposed by the Global Institute for the Prevention of Aggression (GIPA) in September 2023. (Trahan convenes the GIPA.)

The negotiations were actually the result of a much lengthier process. The crime of aggression was included in the ICC’s Rome Statute in 1998, as one of the crimes within the jurisdiction of the ICC (Rome Statute Art 5.1), but the definition of the crime and conditions for the ICC’s exercise of jurisdiction over it had to be negotiated later (Rome Statute Art 5.2.) When agreement on those was reached by consensus of all ICC States Parties in 2010 (see Kampala resolution), the crime—largely at the insistence of the United States—was made subject to an exceptional jurisdictional regime that significantly reduces the ability of the ICC to investigate or prosecute the crime. (For details, see Trahan, Reisinger Coracini, McDougall here and here.)

Further restrictions were placed, or arguably placed, on the ICC‘s exercise of jurisdiction as a result of negotiations in 2017 spearheaded by the U.K. and France (ASP 2017 resolution; see Trahan and McDougall here and here) arguing the restrictions are invalid). As a result, the ICC has neither been able to investigate nor prosecute the crime, which only applies where there has been a “manifest” violation of the UN Charter—such as, although not limited to, Russia’s full-scale invasion of Ukraine. All states, of course, are already bound by article 2.4 of the UN Charter not to commit any violation of the Charter’s use of force provisions. Although the UN Security Council may also refer situations of suspected aggression to the ICC (Rome Statute, Art. 15ter), it has never done so.

As a result of the extensive restrictions on jurisdiction, even when Russia invaded Ukraine and Ukraine accepted the ICC’s jurisdiction on an ad hoc basis (see here and here) and later became a party to the ICC’s Rome Statute including the Kampala crime of aggression amendments, the ICC still lacks the ability to exercise jurisdiction over aggression by Russian or other nationals on the territory of Ukraine. Efforts are thus underway to develop a separate crime of aggression tribunal for the situation of Ukraine established through the Council of Europe. A separate tribunal is being pursued because it was feared that any Rome Statute amendment to harmonize jurisdiction would not come in time to cover the situation of Ukraine and could not be retroactive.

Yet, the ICC was developed as a standing institution to move beyond the ad hoc approach to tribunals that had been pursued during the 1990s (e.g., the Yugoslav Tribunal, the Rwanda Tribunal, the Special Court for Sierra Leone, the Cambodia Tribunal). Resort to an ad hoc tribunal when it comes to the crime of aggression is thus a step backwards in the development of international criminal law, since an ad hoc approach means that only selective justice can be pursued.

A large majority of states present at the July 7-9 negotiations expressed strong support for the harmonization of jurisdiction; basically, small and medium-sized states, in general, desire more jurisdiction before the ICC over the crime so that their states do not become victims of the crime. (See statements during the General Debate.)

However, a small group of states, led by France, the United Kingdom, Canada, Japan, New Zealand, and a handful of other states, opposed the amendment and were able to block its adoption. These states raised technical questions (many that had already been asked and answered during the spring meetings) seemingly in an attempt to “run the clock,” so that no substantive agreement could be concluded during the July session. (For discussion of some of the technical questions raised and answers to them, see Reisinger Coracini and Kreβ.) These states also argued that there had been inadequate time for their questions to be answered—an argument that rang hollow given their active participation during the six months of prior negotiations. In fact, some of the issues related to jurisdiction have been raised (and resolved) during negotiations in the Special Working Group on the Crime of Aggression (2003-2009) and/or at the 2010 Review Conference in Kampala, Uganda.

The same states that blocked the July negotiations have been supportive (at least to some extent) of prosecuting the crime of aggression when it comes to prosecuting Russian nationals before a special tribunal for the invasion of Ukraine (see, e.g., UK proposal). It is therefore extraordinarily hypocritical for these states to support the rule of law in one instance and not more broadly, thereby endorsing only the selective application of justice. Such an approach is at odds with the eloquent words of U. S. prosecutor, Justice Robert H. Jackson, in his opening statement before the International Military Tribunal at Nuremberg:

But the ultimate step in avoiding periodic wars, which are inevitable in a system of international lawlessness, is to make statesmen responsible to law. And let me make clear that while this law is first applied against German aggressors, the law includes, and if it is to serve a useful purpose it must condemn aggression by any other nations, including those which sit here now in judgment.

Support only for the selective application of justice is at odds with a true commitment to the rule of law.

In a positive and welcome change from prior years, civil society was also actively engaged, organizing various side-events, and in statements delivered during plenary sessions. During a side event on “The Devastating Impact on Victims of Aggression and the Case for Harmonization from a Civil Society Perspective” held on July 7 2025, victims from Ukraine, the Democratic Republic of the Congo, Armenia, and Guyana, spoke about the horrors inflicted by aggression or the threat of aggression. The event served as a reminder of why states needed to harmonize jurisdiction.

Disappointingly, at the conclusion of the negotiations, the only agreement that could be reached was that the negotiating process would continue, with further meetings to be held in 2027 and 2029, to finalize agreement. (See ASP resolution.)

Notwithstanding, the holding of the Special Session, with so many states and members of civil society actively engaged in the process and committed to the harmonization of jurisdiction, was an important step towards concluding a final agreement. Unfortunately, in the interval, the ICC cannot provide effective deterrence against the commission of the crime as in most situations it will lack jurisdiction. Thus, the delay caused by France, the United Kingdom, Canada, and their supporters, comes at the cost of the lives of those who will become the crime’s future victims.