Kuberan Hansrajh Kumaresan, Law Student, University of Oxford


Since the invasion of Ukraine on the 24th of February 2022, Russia has, very deservedly, come under great international scrutiny for this violation of the sovereignty of Ukraine and reported perpetration of several international crimes. While there is a wide consensus in the international community that measures must be taken to quell Russian hostility and to demonstrate clear and unwavering support for Ukrainian sovereignty, there is much debate over the exact methods by which the international community, particularly in the legal realm, might go about administering repercussions for these actions.

At the time of writing, there have been a number of steps already taken with this goal in mind. The International Court of Justice (ICJ) has declared Russia’s invasion of Ukraine to be unjustified and ordered it to “immediately suspend the military operations” that it has commenced. This judgement was, as expected, soundly rejected by the Kremlin. The European Court of Human Rights (ECtHR) has expressed that urgent interim measures comprising the Russian government’s need to refrain from attacking civilians, civilian objects, medical establishments and more are necessary to safeguard against violations of the European Convention on Human Rights (ECHR). With respect to prosecuting the individuals involved, the International Criminal Court, led by Karim Khan QC, indicated that there would be an investigation opened into human rights abuses in Ukraine by Russia pursuant to preliminary investigations in 2020. This was done following the receipt of 39 state referrals to the ICC of the situation in Ukraine which allowed the OTP to commence the investigation without prior scrutiny by the Pre- Trial Chamber as is commonplace.  It is pertinent to note that these investigations are not to do with the crime of aggression (which this account is primarily concerned with) but are to do with crimes against humanity, genocide or war crimes carried out on Ukrainian soil. Nonetheless, the ICC will not have jurisdiction over the crime of aggression as Russia and Ukraine are not State Parties to the Rome Statute as is required for ICC jurisdiction(Article 15bis(5) of the Rome Statute).

This article will not address the practical difficulties of setting up a tribunal or according jurisdiction to domestic courts to prosecute the crime of aggression (this has been addressed excellently here) but rather will attempt to provide value to the prosecution of aggression independent of the body that adjudicates this prosecution. It is worth noting however that the likely options are prosecution through domestic courts as detailed here or the creation of an ad hoc international tribunal with the endorsement of the General Assembly similar to that granted to the Extraordinary Chambers in the Courts of Cambodia. With this in mind, this article will set out the need to go beyond the current legal remedies that the international community have adopted and prosecute, specifically, the crime of aggression.

What is the crime of aggression?

As set out in Article 8bis(1) of the Rome Statute, the crime of aggression is described as “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”(emphasis added).  In the instant case, it is accepted that it is beyond reproach that the act of aggression (invasion of Ukraine) is a “manifest” violation of Article 2(4) of the UN charter explicitly prohibiting the “use of force” against the territorial integrity of a state (see pieces by Schmitt and Janik). This is, as recently reiterated by the ICJ in the Armed Activities on the Territory of the Congo case, a contravention of a principle that comprises one of “the most fundamental” in international law.

Why do we need to prosecute it?

While this article will focus on the practical necessity of prosecuting the crime of aggression in the context of the Russian invasion of Ukraine, the doctrinal justifications of the criminalization of aggression are still undoubtedly relevant in illuminating the need for this prosecution. An orthodox view of the normative justification for the criminalization of aggression begins chiefly with the Walzerian account: this suggests that states possess the twin rights of territorial integrity and political sovereignty and aggression is an infringement on these rights. Dannebaum suggests that while it may be the case that the infringement of sovereignty is a relevant concern, the core wrong that aggression seeks to guard against is the “unjustified killing and infliction of human suffering”. Crucially, it is the only crime that makes provision for the unjust killing of combatants and collateral civilians. Without this provision, there would be a huge “gap” in criminal law protection in international conflicts. Thus, the unique protection the prosecution of aggression accords to victims in Ukraine demonstrates why criticisms that suggest this endeavour is unnecessary, due to existing attempts to prosecute other crimes, fall short of the mark .

With regard to the practical justification of prosecuting the crime of aggression, there are two key reasons why this is necessary in the instant case: the greater ambit the crime of aggression has to hold wrongdoers to account and the relative ease of acquiring a conviction.

Firstly, aggression is more capable of holding a greater number of individuals in leadership positions to account than crimes against humanity, genocide and other alternatives that the international community is currently exploring to make Russia answerable for their actions. As is rather uncontroversial (as can be seen here and here), Alexander Lukashenko “allowing” his state of Belarus to be used as an access point for Russia’s entry into Ukraine can in itself be construed as an act of aggression under Art. 8bis(2)(f) of the Rome Statute. Further, as detailed earlier, the crime of aggression essentially encompasses anyone in a position of power who is involved in the “the planning, preparation, initiation or execution” of an act of aggression. As many including Dannebaum note, there are vast amounts of precedent that support a rather expansive scope of the crime of aggression. For instance, the tribunal in the I.G. Farben trial noted that even “persons in the …  industrial fields … who were responsible for the formulation and execution of policies” could be implicated in the crime of aggression. The International Military Tribunal also opined in the High Commandcase that the “statesmen, military leaders, diplomats, and businessmen” who gave Hitler their cooperation could also be deemed as having committed the crime of aggression. While there are those such as McDougall who quite fairly remarks that the Rome Statute conceptualization of aggression might be considerably narrower than that considered by the IMT, this is not an uncontroversial opinion. Ferencz sets out that there are “many possible scenarios” where the ability for an individual to direct others can be “reasonably inferred” even in instances where they do not have a title giving them that authority. He even goes as far as to suggest the acts of “chief legal officers” or “key advisors” can fall within the Rome statute definition of the crime of aggression. Thus, it seems to be the case that even if it is conceded that the Rome Statute definition of aggression is slightly narrower than when aggression was conceived, it is still sufficiently broad such that it captures the wrongdoing of individuals, particularly those in leadership positions, not otherwise held criminally liable.

Secondly, it is perhaps easier to get a conviction for a crime of aggression as compared to other war crimes. As expressed at length by multiple institutions, intent is key to successfully proving a crime against humanity or genocide. This requires in-depth investigation to find recordings, and memos and causes prosecutors great difficulty. As Solis notes, it often means only being able to indict the “field commander of the unit that actually dropped the bomb” but not individuals in greater positions of power due to this apparent difficulty of obtaining evidence. The difficulty of proving intent for the crime of genocide notwithstanding the great deal of evidence already present in Ukraine to evidence the harm visited upon Ukrainian citizens seems to quite strongly affirm that prosecution for a crime such as aggression is more straightforward. Moreover, the public broadcast of a meeting the Russian Security Council had could be construed as “planning” or preparation” under Art. 8bis(1) such that they would be liable specifically for aggression under the Rome Statute. Considering the act of starting an aggressive war is in and of itself a crime, there appears, on the surface, to be clear evidence of the necessary kind for a successful prosecution. Thus, prosecuting the crime of aggression would seemingly present less, even if somewhat, of an issue.


Due to the need to protect combatants and the practical benefits of prosecuting the crime of aggression in particular, it is of paramount importance the international community acts swiftly to craft the necessary institutions to preside over proceedings concerning the crime of aggression. There is no doubt that the path to justice in such a difficult situation is long and arduous. Yet, we owe it to the people that have suffered and the people that are suffering to acknowledge , in all forms,  the pains this invasion has visited upon them and act to give them closure.