The concept of aggression in modern international law is rooted in a complex history of war and conflict. Defined as the use of armed force by one state against another in the absence of the justification of self-defense or the authorization of the United Nations, aggression has been a recurring issue on the global stage. The legal framework surrounding the crime of aggression has evolved over the years, with the Rome Statute of the International Criminal Court (ICC) now confirming a crucial definition and criminalization of aggression.

The Russian Federation, under President Vladimir Putin, has been accused of committing acts of aggression against Ukraine, raising the need for accountability. In this article, we focus on two practical options for holding Russia and President Putin accountable for these alleged acts of aggression: the establishment of an international tribunal through a UN General Assembly (UNGA) resolution, or the formation of a multinational court created by member states.

It is important to note that either of these options would supplement and support the work of the International Criminal Court (ICC); they would not replace the latter. But they would expand its reach and enable it to overcome key jurisdictional issues. The ICC simply does not have jurisdiction over the crime of aggression in the Ukraine conflict. An international tribunal or multinational court such as those described in this article could be created to withstand any legal argument that head-of-state immunity would apply to and thus shield President Putin and his ministers from prosecution.

Either of these options can be a successful model for holding perpetrators to account for international crimes. Other options that have been proposed, such as a domestic hybrid court or a regional European court, would be a waste of time. And time is of the essence.

The Crime of Aggression in Modern Times

The concept of aggression as a crime under international law is rooted in the horrors of World Wars I and II, but various efforts to police it have fallen short.

The Kellogg-Briand Pact of 1928 renounced war as a means of settling international disputes. But while it enjoyed popular support — with dozens of signatory nations spanning the globe — it lacked enforcement mechanisms;

The United Nations Charter, adopted in 1945, outlawed the use of force in international relations except in cases of self-defense or Security Council authorization. But, the Charter does not provide a clear definition of aggression or prescribe legal consequences for its commission;

Adopted in 1998, the Rome Statute established the ICC to prosecute individuals for genocide, crimes against humanity, war crimes, and the crime of aggression. However, it was not until a review conference in 2010 — 12 years after the finalization of the Statute’s other provisions — that a comprehensive definition of aggression and procedures for its criminalization were formulated and prepared for ratification. And given Russia’s status as a non-party to the Rome Statute, these terms exclude it from ICC jurisdiction.

Hence, there is a critical need for another way to prosecute Russia’s aggression. In this regard, there are only two realistic and practical options: 

Option One: Establishment of an International Tribunal via UN General Assembly Resolution

The preferred option would be to establish an international tribunal through a UN General Assembly resolution. This resolution could recommend that the UN Secretary-General enter into a bilateral agreement with Kyiv to create a Special Tribunal for Ukraine on the Crime of Aggression. This approach would require broad international consensus and support from the member states of the UN General Assembly, offering a relatively impartial and comprehensive method for addressing the issue. Ideally, the tribunal would operate independently of the UN Security Council, whose veto-wielding members — including Russia —  could otherwise create obstacles to addressing politically sensitive matters of this character. The proposed tribunal would be staffed with international judges and legal experts to ensure impartiality, and it would provide a forum for the presentation of evidence and testimony by both sides.

Benefits of this option:

• Automatic International Legitimacy: The fact that this option would be rooted in the support of the United Nations General Assembly would demonstrate a strong commitment to upholding international law and holding aggressors accountable. This would enhance the tribunal’s credibility and perceived fairness from day 1.
• Global Consensus: To pass a General Assembly resolution in this particular situation, a two-thirds majority of member states would be required. Achieving such consensus would send a powerful message that the international community is united in its determination to address the situation. This could exert significant pressure on the accused state to cooperate and participate in the proceedings.
• Freedom From Security Council Politics: The General Assembly option would avoid the political complications of veto powers in the Security Council, ensuring that the process would be less susceptible to the influence of a few powerful states, making it potentially more impartial and just.

Option Two: Establishment of a Multinational Tribunal Established by UN Member States

Another option with historical evidence of success involves a core group of UN member states establishing a to set up a Multinational Tribunal for Ukraine on the Crimes of Aggression. This approach would allow states directly or indirectly affected by the situation to take matters into their own hands and establish a tribunal through international agreement.

A core advantage of this method is that it would be spared both the potential vetoes of the Security Council, and the political complexities of the two-thirds consensus requirement in the General Assembly. It would also offer greater flexibility in terms of shaping the tribunal’s structure, composition, and jurisdiction.

But considerable disadvantages could include concerns about the tribunal’s legitimacy and impartiality, as it could be seen as driven by the interests of the states that established it. To this end, it would be imperative that its founding states included representatives of both the Global North and South; it should not be a Euro-centric effort.

The International Military Tribunals at Nuremberg and Tokyo are historic examples upon which this multinational tribunal could draw. In large measure, the international community has done this before.

Benefits of this option:

• Speed and Flexibility: A core group of interested states can come together swiftly to create a multinational tribunal, bypassing the often time-consuming processes of both the UNGA and the Security Council. Response times can be crucial when it comes to addressing urgent situations.
• Global Support: While this approach may begin with a core group of states, it allows for the broadening of support from member states worldwide. Other countries can join the tribunal directly or indirectly, thereby signaling their commitment to holding aggressors accountable. This global support can continue to enhance the effectiveness and perceived legitimacy of the tribunal.
• Jurisdictional Breadth: The flexibility of this approach means that states can tailor the tribunal’s jurisdiction and composition to fit the unique circumstances of the situation. This adaptability can facilitate a more comprehensive and effective response to Moscow’s alleged aggression.

Time is of the Essence

Each option has distinct advantages that cater to different aspects of addressing Russian aggression against Ukraine. The choice between these options will depend on factors such as the political will of the international community, the urgency of the situation, and the desired level of enforcement mechanism’s, operational flexibility, and perceived legitimacy. Ultimately, the pursuit of accountability and justice should remain at the forefront of the decision-making process, with the hope of preventing further acts of aggression and upholding the principles of international law. To this end, time truly is of the essence. A tribunal must be set up within the year lest we suffer a failure of the will to do so — similar to what went wrong with the push for accountability for Syria.  The international community must stay focused and not permit other world events to lessen the urgency of immediate action.

The alleged acts of aggression by the Russian Federation in Ukraine demand accountability and justice. The practical options presented here provide distinct legal avenues for addressing these allegations. The choice among these options will depend on the willingness of the international community to take action, navigate political obstacles, and ensure the fairness and impartiality of the legal process.

Regardless of the path chosen, the pursuit of accountability for crimes of aggression remains a fundamental principle of international law and an essential step towards maintaining global peace and security.

*Irwin Cotler was the Minister of Justice and Attorney General of Canada (2003-2006); Hans Corell was the UN Undersecretary-General for Legal Affairs (1994-2004); David Crane was the Founding Chief Prosecutor of the UN Special Court for Sierra Leone (2002-2005); and David Scheffer was the inaugural US Ambassador at Large for War Crimes Issues (1997-2001).