In 2002, upon the entry into force of the Rome Statute, the International Criminal Court (ICC) began its operation with an aim of ending impunity for the most serious crimes; to have a permanent means of prosecuting war crimes, the crime of genocide, crimes against humanity, and crimes of aggression. In the twenty-three years since the ICC began its operation, and in the seven years since the Court’s jurisdiction for the crime of aggression has been active, the crime of aggression has not once been investigated or prosecuted. This lack of prosecution and investigation is not due to a lack of aggression. Russia’s full-scale invasion of Ukraine and other acts of aggression are taking place, and there is international public interest in having these crimes dealt with at a judicial level. Despite this apparent international interest in having a permanent place to prosecute acts of aggression, an incredibly restricted jurisdictional regime —attached only to the crime of aggression and not to any of the other three core crimes— effectively prevents the ICC from ever dealing with crimes of aggression. 

When the Rome Statute for the ICC was adopted in 1998, the crime of aggression was included as one of the four core crimes of the ICC; however, a definition of the crime was not included due to disagreements among the participating States. In 2010, in Kampala, a definition of the crime was adopted, and a jurisdictional regime different from the one used for the other three crimes was created. This new, exceptional, jurisdictional regime, outlined in Articles 15bis and 15ter of the Rome Statute, applies only to acts committed by nationals of State Parties on the territory of other State Parties, and further restricts jurisdiction by allowing State Parties to reject the ICC’s jurisdiction over aggression. 

From 7-9 July 2025, a Special Session of the Assembly of State Parties (ASP) to the Rome Statute convened to undertake a mandated review of the Kampala amendments on the crime of aggression. This ASP presented a rare opportunity to finally harmonize the ICC’s jurisdiction over all four core crimes — to bring jurisdiction for the crime of aggression in line with that of the other three crimes.

For six months leading up to this Special Session, the Working Group on Amendments (WGA) met regularly to prepare and to discuss varying State positions on this situation. In the preparatory WGA meetings, most States were in favour of harmonizing jurisdiction. A group of 37 States, calling themselves “the Group of Friends,” and many others, hoped the Special Session would conclude with a new amendment to the Rome Statute and harmonized jurisdiction for all four core crimes. The Group of Friends, leading up to the special session, organized meetings around the world in an effort to promote potential reform. The Group of Friends included Austria, Belgium, Bulgaria, Chile, Costa Rica, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Germany, Greece, Guatemala, Iceland, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Sierra Leone, Slovakia, Slovenia, Spain, State of Palestine, Sweden, Switzerland, Timor Leste, Ukraine, Vanuatu, and Zambia.  

A much smaller group of States, spearheaded by Canada, France, Japan and the United Kingdom, adamantly refused to consider the possibility of harmonizing all four crimes at the July Special Session. In the six-month lead-up to the Special Session, each of these four States spoke in favour of collaborating with other State Parties and having a productive review session. Still, none were willing to consider the genuine desire of the majority of States to harmonize the ICC’s jurisdiction. 

Delegates from these States would repeatedly pose the same technical legal questions, and representatives from the Group of Friends and civil society would repeatedly provide sound legal responses. Two of the primary, frequently-repeated concerns presented by States that were against harmonization were that the Kampala amendment did not have enough State ratifications to suggest present interest in amending jurisdiction and that any amendment would cause too much fragmentation of the Rome Statute. In response to these concerns, State representatives and civil society would remind the WGA that Kampala, with 49 Ratifications, is the most widely ratified amendment to the Rome Statute. Additionally, any amendment to a core crime establishes a new subregime, a practice often applied to Article 8. Further description of the dialogue held at the WGA meetings can be found in the ICC’s Report of the Working Group on Amendments Regarding the Exercise of Jurisdiction with Regard to the Crime of Aggression. ^[1]

The harmonization-opposing States specifically emphasized a desire for the Special Session to be collaborative, maintain the unity of the State Parties, strengthen the ICC, and, most importantly, be a three-day discussion exclusively about the pros and cons of the decisions made in Kampala 15 years ago. Harmonization was not an option for this group.

At the Special Session, the opposition of fifteen State Parties was sufficient to block adoption of the amendment; two observer States also voiced strong opposition. The States Parties that stopped the adoption of the amendments were Argentina, Australia, Brazil, Burkina Faso, Canada, France, Guatemala, Japan, Kenya, Malia, New Zealand, Norway, the Republic of Korea, the United Kingdom, and Uganda. The opposing observer States were the United States and China. In addition to opposing the amendment, the representative from the U.S. issued a threat to the Court, noting that unless all ICC action regarding Israel and the United States is stopped, that “all options [for the U.S.] would remain on the table” and that the U.S. “will use all appropriate and effective diplomatic, political, and legal instruments to block the ICC’s overreaching abuse of power.” ^[2]

One must question the motivation of the harmonization-opposing States to squash the progressive development of the Rome Statute framework. Each of these States seems to be supportive, at least in public, of creating an ad hoc tribunal to prosecute Russia for acts of aggression in Ukraine, but they are unwilling to extend the same authority to the ICC—a Court they claim to support, a Court which they claim they want to strengthen, and a Court that cannot, in its current legal capacity, fulfil its intended role. ^[3,4,5] These States do not seem to take issue with the jurisdictional regime used for war crimes, crimes against humanity, and the crime of genocide. Why is it that the crime of aggression is still, 27 years after Rome, treated so differently from the other three crimes? Why is it that these States encourage the use of ad hoc tribunals for dealing with acts of aggression but not the ICC? 

Recent sanctions and harmful and threatening sentiment from the U.S.A. towards the ICC may be one reason that the harmonization-opposing States strongly reject harmonization: each opposition State is in a very important, long-term, and currently tumultuous relationship with the U.S. Additionally, these States generally enjoy stronger military capabilities, have greater international reach, and advanced economies, when compared to many of the other State Parties to the Rome Statute. Four out of seven G7 States are part of the opposition group, another is the U.S., and the outliers in this forum are Germany and Italy. It appears that smaller States, those more susceptible to being victims of acts of aggression and realistically less likely to be aggressors themselves, are more supportive of harmonization. 

The threshold for prosecuting the crime of aggression, as defined in Article 8bis of the Rome Statute, requires that an act of aggression “by its character, gravity and scale, constitutes a manifest violation of the Charter of the United Nations” is incredibly high. A harmonized jurisdictional regime would not alter this threshold. Instead, it would allow the ICC the opportunity to apply this high threshold. If all four crimes were actually able to be dealt with at the ICC, and an individual from any harmonization-opposing State were to commit an act of aggression, the aggression would still have to surpass the “manifest violation” threshold for the situation to reach the ICC. Regardless of the ICC’s manifest violation threshold, these States, and all State Parties, are bound by the UN Charter and Article 2(4), which requires members to refrain from the use of force.

The long-term success and stability of the ICC rest on the support of its Member States. Division in State Party decision-making risks undermining the Court’s stability and makes it easier for the ICC’s adversaries to question its legitimacy and pose increasing threats. Canada, France, the UK, Japan, and others, in a small number, were able to stop the will of the majority of other States and prevent the ICC from addressing what it was designed to deal with. The only outcome of this session is the decision to meet again in 2027 and 2029, and to reconsider everything that has already been discussed.

If Canada, the UK, and others do not support the ICC’s ability to deal with aggression, the same way it deals with the other three core crimes, why then did they ratify Rome? Was it to look good among international political peers? Did these States ratify with the hope that the crime of aggression would never develop beyond the 1998 Rome Statute framework? Why exactly are some States so adamantly against harmonization? These questions do not have legal answers, and it would be erroneous to assume that any of the lawyers advising the involved governments have a better understanding of the law at issue than others. Canada does not have a better grasp of the problem than Germany, and Liechtenstein is not more knowledgeable than France (the opposite is true as well, of course). This difference in stance is far from legal.

Ultimately, the rule of law requires that all law, international or not, be applied invariably and impartially. In an idealized globalized world, the ICC does not take political pressure into account when issuing arrest warrants or developing its own jurisprudence. If lawyers and the global community genuinely want the ICC to function effectively, it must be free from political influence, or at the very least, be free from exceptionally patent political influence. To suggest that any judicial system, international or not, could ever be completely free from political pressure would be incredibly naive and not at all realistic. International relations and national affairs will always direct the way States involve themselves in international legal matters. However, to uphold the integrity of, and any trust held in, international legal systems, the incredibly transparent political will of a minority of involved States cannot forever dominate the functioning of any international legal system. To witness a group of States that pride themselves on being democratic nations with high levels of judicial independence and low levels of corruption, act so contrary to their claimed values is incredibly ironic. The failure to harmonize the jurisdiction of the ICC at the July Special Session did not stem from any real legal issue; rather, it is a prime example of international politics overtly interfering with the international legal order.