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The Crime of Aggression: Why Ukraine Needs a Special Tribunal

Authored By: Emma Lewis

University of South Wales

Abstract

Russia’s invasion of Ukraine shattered not only borders but the illusion that international law  can hold aggressors to account. While war crimes garner attention, the leadership-level crime  of aggression remains untouched. This article calls for a Special Tribunal to prosecute  Russia’s senior officials, exposing jurisdictional gaps and the ethical cost of inaction. It  argues that holding leaders accountable is both a legal necessity and a moral imperative, and  a test of whether international law can still speak when global peace is at stake.

Introduction

In February 2022, the invasion of Ukraine marked the peak of an aggressive campaign that  began with Crimea’s annexation in 2014 and escalated through hybrid warfare. The full-scale  attack violated Article 2(4) of the UN Charter, which bars the use of force against state  sovereignty. Despite global condemnation and extensive sanctions, the leadership-level crime  of aggression remains unaddressed. The ICC lacks jurisdiction: Russia never ratified the  Rome Statute or Kampala Amendments, and Ukraine has not adopted the aggression  provisions. A UN Security Council referral is blocked by Russia’s veto. In June 2025,  Ukraine and over 40 states partnered with the Council of Europe to establish a Special  Tribunal. Its creation sends a clear message: waging war is not just geopolitics; it is a  criminal act demanding personal accountability.

Main Body

Legal Gaps in Prosecuting Aggression

Aggression is a leadership-level crime targeting those who authorise war, not those who fight  it. Defined as the use of armed force against another state’s sovereignty in breach of the UN  Charter,1it is widely viewed as the “supreme international crime”,2 yet remains  unprosecutable in the context of Russia’s invasion of Ukraine.

The International Criminal Court (ICC) was granted jurisdiction over aggression through the  Kampala Amendments in 2010,3 but this jurisdiction is conditional. Either both states  involved must ratify the Amendments and accept jurisdiction, or the UN Security Council must refer the case. Russia, as a permanent member, can veto such referrals,4and neither  Russia nor Ukraine has ratified the aggression provisions.5

Ukraine has accepted ICC jurisdiction for other crimes,6 but this exclusion leaves the  architects of war shielded from accountability. The ICC can investigate atrocities committed  during the conflict, but it cannot prosecute the act that initiated it.

This legal gap undermines the credibility of international law. In response, a Special Tribunal  for the Crime of Aggression has been created,7formally established with the Council of  Europe on 25 June 2025. It will prosecute Russian political and military leaders, bypassing  ICC limitations and excluding immunity for sitting officials.8

This tribunal offers more than legal remedy; it affirms that the decision to wage war is a  punishable act and reasserts the foundational principle that no leader is above the law.

The Case for a Special Tribunal

On 25 June 2025, Ukrainian President Volodymyr Zelenskyy and Council of Europe  Secretary General Alain Berset signed an agreement establishing the Special Tribunal for the  Crime of Aggression against Ukraine.9 This marks the first dedicated mechanism since  Nuremberg to prosecute leadership-level aggression.

The tribunal’s mandate is direct and unprecedented: it will prosecute senior political and  military officials, including sitting heads of state, for planning or executing Russia’s war  against Ukraine. The statute expressly excludes immunity protections,10 signalling a shift in  international norms that leadership must not shield criminality.

Rather than relying on the ICC’s limited framework, the tribunal’s authority derives from  Ukraine’s territorial sovereignty. This bypasses the Kampala Amendments and Rome Statute  jurisdictional constraints,11 enabling prosecution where the ICC cannot. Its legal foundation is  hybrid, combining its statute, relevant treaties, customary international law, and Ukrainian  law.12

Trials in absentia are permitted, subject to safeguards. Defendants retain rights to  representation and may request a retrial if apprehended, unless waived.13 The tribunal emerged from multilateral collaboration. A Core Group of over 40 states,  alongside the Council of Europe and the European Union, drafted its framework.14 These  texts were endorsed at ministerial level in Lviv on 9 May 2025 and adopted by the  Committee of Ministers on 24 June.15

More than a legal tool, the tribunal declares that aggression is not a sovereign prerogative but  a criminal act demanding accountability.

Symbolism, Deterrence, and Legal Innovation

The Special Tribunal is not just a legal mechanism; it is a moral declaration. It affirms that  leadership-level aggression is a punishable crime and sets a precedent that war cannot be  waged without consequence.

Its symbolism is profound. The tribunal challenges the idea that sovereign power shields  leaders from accountability. It reframes war as criminal when unlawfully initiated, echoing  Nuremberg’s legacy where aggression was deemed the “supreme international crime”.16 As deterrence, it shifts the calculus for state leaders. The prospect of personal criminal  liability, even in absentia, may influence decisions to initiate conflict. While enforcement  remains complex, the tribunal’s existence signals evolving norms: impunity is no longer  guaranteed.17

Legally, it is a novel construct. Blending domestic and international law, it bypasses  traditional immunity doctrines,18 permits in absentia trials with safeguards,19 and  complements institutions like the ICC by addressing jurisdictional gaps.20 Its creation reflects multilateral innovation. The Core Group’s collaboration, across more  than 40 states, shows legal adaptability.21 Ukraine’s territorial jurisdiction and the Council of  Europe’s support provide legitimacy and sovereign grounding.22

Lastly, the tribunal gives voice to victims. As Veronika Velch of Amnesty International  Ukraine stated, it must close “accountability gaps”23 and ensure aggression is properly  investigated.

Discussion

The Special Tribunal marks a turning point in international law. It confronts longstanding  inertia around leadership-level accountability and offers a replicable model for future  conflicts.24 By prosecuting the crime of aggression, it reasserts the principle that initiating  unlawful war is not a sovereign prerogative but a punishable offence.

Its creation also reflects Ukraine’s agency in shaping its justice narrative.25 Rather than  relying solely on external institutions, Ukraine has led the legal and diplomatic effort to  establish a tribunal grounded in territorial jurisdiction and multilateral legitimacy.26 The tribunal’s success will hinge on sustained political will, adequate funding, and  meaningful public engagement.27 As noted by Prosecutor General Ruslan Kravchenko,  Ukraine is preparing to fully participate in the tribunal’s work, including evidence provision  and legal representation.28 Continued support from international partners, including the G7  and EU, will be essential to operationalising the tribunal and ensuring its long-term  credibility.

Conclusion

Ukraine’s demand for justice is not only legal, but also a plea from a devastated nation,  echoed by millions who have lost homes, loved ones, and peace. Constrained by political and  jurisdictional limits, existing institutions could not bear that weight alone. The Special  Tribunal enters this void to honour suffering, restore truth, and reaffirm global conscience. It tests the relevance of international law in the face of state aggression. If it succeeds, it  proves leaders cannot hide behind borders; if it fails, the silence will expose the fragility of  global justice.

Bibliography (OSCOLA-Formatted)

Primary Legal Instruments

  • Charter of the United Nations (adopted 26 June 1945, entered into force 24 October 1945) 1 UNTS XVI, art 2(4)
  • Rome Statute of the International Criminal Court (adopted 17 July 1998, entered into force 1 July 2002) 2187 UNTS 90, arts 15 bis–ter, 27
  • Assembly of States Parties, ‘Resolution RC/Res.6’ (Kampala, 11 June 2010) • Agreement between the Council of Europe and Government of Ukraine on the Establishment of the Special Tribunal for the Crime of Aggression (25 June 2025) • Draft Statute of the Special Tribunal for the Crime of Aggression against Ukraine (2025), arts 18, 27

Judicial Reports and Statements

  • Report of the International Military Tribunal for Nuremberg, Trial of the Major War Criminals (1946) [41]
  • Robert H Jackson, ‘Opening Statement at the Nuremberg Trials’ (1945) Institutional and Government Sources
  • ICC, ‘States Parties to the Rome Statute’ <https://asp.icc-cpi.int/states-parties> accessed 28 July 2025
  • ICC, ‘Declarations Accepting Jurisdiction of the ICC’
  • Council of Europe, ‘Special Tribunal Legal Framework Summary’ (2025) • Council of Europe, ‘News Release: Core Group Meets to Finalise Tribunal Draft’ (2025)
  • Council of Europe Committee of Ministers, ‘Official Adoption of the Tribunal Framework’ (24 June 2025)
  • Council of Europe, ‘Special Tribunal for Ukraine: Secretary General Welcomes Completion of Technical Discussions’ (21 March 2025)
  • European Commission, ‘International Coalition Agrees on the Establishment of the Special Tribunal’ (9 May 2025)
  • Foreign, Commonwealth & Development Office, ‘Foreign Secretary Speech in Lviv on the Special Tribunal’ (9 May 2025)
  • Ukrinform, ‘Kravchenko Believes Law on NABU, SAPO Powers Will Not Harm Dialogue with Partners’ (23 July 2025)

NGO and Academic Commentary

  • Amnesty International Ukraine, ‘Reaction to the Special Tribunal Agreement’ (26 June 2025)
  • Jennifer Trahan, Legal Analysis of the Special Tribunal for the Crime of Aggression against Ukraine (2023)

1 Charter of the United Nations (adopted 26 June 1945, entered into force 24 October 1945) 1 UNTS XVI, art 2(4).

2 Report of the International Military Tribunal for Nuremberg, Trial of the Major War Criminals (1946) [41].

3 Assembly of States Parties, ‘Resolution RC/Res.6’ (Kampala, 11 June 2010).

4 Rome Statute of the International Criminal Court (adopted 17 July 1998, entered into force 1 July 2002) 2187 UNTS 90, art  15 bis–ter.

5ICC, ‘States Parties to the Rome Statute’ https://asp.icc-cpi.int/states-parties accessed 28 July 2025.

6ICC, ‘Declarations Accepting Jurisdiction of the ICC’.

7 Council of Europe and Government of Ukraine, ‘Agreement on the Establishment of the Special Tribunal for the Crime of  Aggression’ (25 June 2025).

8 Draft Statute of the Special Tribunal for the Crime of Aggression against Ukraine (2025), art 27.

9 Agreement between the Council of Europe and Government of Ukraine on the Establishment of the Special Tribunal for the  Crime of Aggression (25 June 2025).

10 Draft Statute of the Special Tribunal for the Crime of Aggression against Ukraine (2025), art 27.

11 Rome Statute of the International Criminal Court (1998) 2187 UNTS 90; Assembly of States Parties, ‘Resolution  RC/Res.6’ (Kampala, 11 June 2010).

12 Council of Europe, ‘Special Tribunal Legal Framework Summary’ (2025).

13 Draft Statute (n 2), art 18.

14 Council of Europe, ‘News Release: Core Group Meets to Finalise Tribunal Draft’ (2025)

15 Council of Europe Committee of Ministers, ‘Official Adoption of the Tribunal Framework’ (24 June 2025).

16 Report of the International Military Tribunal for Nuremberg, Trial of the Major War Criminals (1946) [41].

17 Jennifer Trahan, Legal Analysis of the Special Tribunal for the Crime of Aggression against Ukraine (2023) 

18 Rome Statute of the International Criminal Court (adopted 17 July 1998, entered into force 1 July 2002) 2187 UNTS 90,  art 27.

19 Draft Statute of the Special Tribunal for the Crime of Aggression against Ukraine (2025), art 18.

20 Assembly of States Parties, ‘Resolution RC/Res.6’ (Kampala, 11 June 2010).

21 Council of Europe, ‘News Release: Core Group Meets to Finalise Tribunal Draft’ (2025)

22 Agreement between the Council of Europe and Government of Ukraine on the Establishment of the Special Tribunal for  the Crime of Aggression (25 June 2025).

23 Amnesty International Ukraine, ‘Reaction to the Special Tribunal Agreement’ (26 June 2025) 

24 Robert H Jackson, ‘Opening Statement at the Nuremberg Trials’ (1945). 

25 Foreign, Commonwealth & Development Office, ‘Foreign Secretary Speech in Lviv on the Special Tribunal’ (9 May  2025).

26 European Commission, ‘International Coalition Agrees on the Establishment of the Special Tribunal’ (9 May 2025).

27 Council of Europe, ‘Special Tribunal for Ukraine: Secretary General Welcomes Completion of Technical Discussions’ (21  March 2025). 

28 Ukrinform, ‘Kravchenko Believes Law on NABU, SAPO Powers Will Not Harm Dialogue with Partners’ (23 July 2025).

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