From the early days of Russia’s war of aggression against Ukraine, there have been clarion calls for individual criminal accountability. The blatant act of military aggression ordered by Russia’s political leadership, and the prolonged, indiscriminate bombardment of towns and villages on a scale not seen in Europe since World War II, has upended the international legal order. While Western states have rallied to sustain their Ukrainian ally with political and military support, politicians, lawyers and scholars speak of the critical need for this aggression to be prosecuted in a special, international court of law. But political reluctance on key legal issues has led to deadlock, and resolute diplomatic action is needed to progress the vital issue of legal accountability.

Creating a new ‘Special’ Tribunal for the Crime of Aggression

The need for a new court is deemed necessary because the International Criminal Court (ICC) lacks jurisdiction for the crime of aggression, but otherwise has the ability to prosecute a full panoply of war crimes, crimes against humanity and genocide. Indeed, the court has already issued arrest warrants for President Vladimir Putin and Commissioner for Children’s Rights, Maria Lvova-Belova, for the war crime of unlawfully deporting children from Ukraine into Russia.

But because ICC member states specifically agreed that only the nationals of ICC member states could be prosecuted for the crime of aggression, this crime will never be utilised in the current Ukrainian context, because Russia is not a member. While ICC member states could agree to amend this jurisdictional limitation, that is a distinctly unlikely prospect, given the diplomatic effort that would require – two thirds of member states would have to agree to any change to the court’s founding document, the Rome Statute. Hence the need for a special tribunal to fill the ‘accountability gap’ for a crime that has been labelled the supreme international crime, from which all other crimes follow.

However, how such a new court would look – both in practice and in substance – has produced a marked environment of disagreement among Ukrainian allies, ‘referred to as the core group of 40’, which includes Ireland, that are otherwise resolutely united behind the Ukrainian cause. This division has led to deadlock. Two years on from the start of this current phase of the Ukraine-Russia conflict, these states simply cannot agree on how a tribunal should be constituted. As a result, the accountability debate has stagnated, and no tangible progress has been made towards the realization of a tribunal for the crime of aggression.

The ‘Model’ Impasse

Two key points of disagreement are evident. First is the mode of creation. Given the severity of the Russian aggression and the impact upon the global democratic order, Ukraine desires a fully-fledged international tribunal, ideally created by way of multilateral treaty and/or under the auspices of the UN system, via approval of the General Assembly. As well as enhanced legitimacy, this method would entail enhanced and necessarily important powers of judicial enforcement. However, this method causes anxiety among certain states that worry about the precedent this model would set. The concern being: what would prevent more tribunals being created for other contexts where aggression is alleged by one or more states against another? 

The alternative method of creation is that of a hybrid international court: domestic special chambers within the Ukrainian legal system, but with international elements. This option appears to have more support among allied states, as it is the path of least resistance in terms of initial creation and would arguably enhance local ownership. But it is considered that this model would have reduced legitimacy as it is opposed by Ukraine, and would have admittedly weaker powers of judicial enforcement.

The second pressing issue is that of immunities. Ordinarily, in the horizontal relationship between states, high-ranking state officials enjoy personal immunity. States understand and agree that they cannot arrest each other’s high-ranking officials. However, in the vertical relationship between states and ‘international courts’, high-level state officials such as the Head of State typically enjoy no immunity if the jurisdiction of that court provides for such. This position was enunciated in the famous dicta of the International Court of Justice in the Arrest Warrant case, and similarly confirmed by the Appeals Chamber of the ICC, when it held that former President of Sudan (a non-member of the ICC), Omar Al-Bashir, had no immunity before the ICC.

Therefore, a fully-fledged international tribunal for the crime of aggression, it is posited, would have the inherent power to displace for the purpose of prosecution the immunity of persons who would otherwise enjoy it. While a domestic hybrid chamber would not.

Another important although under-discussed factor is the issue of cost. Establishing and funding either a new international or hybrid tribunal will be an expensive and years-long financial commitment for supporting states.

Interim Evidentiary Progress

Amid this political deadlock, certain positive progress in the area of evidence preservation has been made. In July 2023, under the auspices of Eurojust, the International Centre for the Prosecution of the Crime of Aggression against Ukraine was set up in The Hague, with an operational mandate to preserve evidence and support national jurisdictions in their respective domestic investigations into the crime of aggression. Notably, the ICC has committed to cooperate with this mechanism and Eurojust’s Joint Investigation Team through the sharing of information. Similarly, a Register of Damage for Ukraine has also been set up under the auspices of the Council of Europe, designed to record the extent of loss and injury that may be the subject of future compensatory claims, ideally to be adjudicated by an international compensation mechanism. These are positive steps and lay important evidentiary foundations for any future special tribunal.

Bridging the Gap

The question now is how to resolve the impasse. States are committed to ongoing dialogue but cannot seem to articulate the ‘solution’, to demarcate the ‘landing zone’, and to decide how to ‘bridge the gap’ that currently exists. It is time to move beyond the general to the specific. A useful and concrete next step would be to debate potential draft statutes for both an international and a hybrid court in a diplomatic, plenipotentiary conference. Civil society has already started this discussion. The core group of 40 could designate a Working Group to prepare two draft statutes for debate. Similar conferences occurred in the years leading up to the creation of the ICC, before agreement could finally catalyse.

Whether a tribunal is international or hybrid, the core of either statute would largely be the same and uncontroversial – such as the core legal framework, the rights of the accused, and the basic rules of procedure. Importantly, such a forum would provide states with a venue to definitively confront the roadblock issues mentioned above, to debate and negotiate potential wording. Such a process would assist to provide a degree of clarity as to whether there is any flexibility to agree on the exact modalities of the special tribunal’s creation and its judicial reach. If tangible progress is not realistic, perhaps diplomatic efforts could then be redirected towards exploring amending the Rome Statue framework.

States like Ireland can play a key role in leading such a debate, given its long-standing support for international accountability mechanisms, including for the ICC’s investigation in Ukraine, and its respected role in international diplomacy. On this important issue, dialogue on a tribunal should now transition to concrete decision-making. We should not let Ukraine wait any longer.

(Note: This article is cross-posted from The Azure Forum, where it was originally published as part of the Strategic Insights series)