Roundtable Blog: “One Year Since Ukraine’s Ratification of the Rome Statute”
Editor’s Note
This blog marks the first anniversary reflection on one of Ukraine’s most consequential legal milestones — the ratification of the Rome Statute. Presented as part of PILPG’s Ukraine Peace Negotiations Working Group, this roundtable brings together expert perspectives from leading members of the PILPG Peace Fellows network. Each contributor examines how Ukraine’s formal accession to the International Criminal Court (ICC) has shaped its justice architecture, legal capacity, and international standing during an ongoing war of aggression.
Published under the Lawyering Justice banner, this post continues PILPG’s effort to connect legal analysis with peace strategy and to situate Ukraine’s accountability progress within a broader framework of international law and diplomacy. The reflections below assess how ICC membership is reshaping Ukraine’s domestic legal order, transforming cooperation with international institutions, and influencing global debates about aggression, sovereignty, and justice during active conflict.
This roundtable also contributes to a forward-looking policy conversation: how Ukraine and its partners can consolidate an enduring system of accountability that integrates the ICC, the newly established Special Tribunal for the Crime of Aggression, and national war crimes mechanisms. Together, these insights reaffirm that accountability is not a post-war ideal but a central element of Ukraine’s pursuit of a just and sustainable peace.
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On 25 October 2024, Ukraine deposited its instrument of ratification of the Rome Statute, and on 1 January 2025, the Statute officially entered into force for Ukraine. This moment marked more than the conclusion of a decades-long legal journey — it represented Ukraine’s determination to enshrine accountability within its national identity even as it continues to defend itself against Russia’s war of aggression. The decision to join the International Criminal Court (ICC) amid active conflict underscored a powerful principle: that justice is not a luxury of peace, but a condition for achieving it.
In this roundtable blog, PILPG’s Peace Fellows and experts reflect on Ukraine’s first year as a State Party to the ICC through five guiding questions — exploring the most significant impacts of ratification, its influence on Ukraine’s domestic justice system, the evolving cooperation with the ICC, the broader implications for global accountability, and the strategic priorities that lie ahead.
What has been the most significant impact of Ukraine’s ratification of the Rome Statute so far?
Dr. Paul R. Williams, Rebecca Grazier Professor of Law and International Relations at American University
Ukraine’s ratification of the Rome Statute has fundamentally anchored its accountability framework within the international rule of law. By formally joining the ICC system, Ukraine transformed years of ad hoc cooperation into a durable legal commitment that reinforces its credibility as a state dedicated to justice for atrocity crimes. This ratification has also elevated Ukraine’s standing among nations seeking to strengthen the global architecture for accountability. The move has reassured victims and civil society actors that accountability for war crimes, crimes against humanity, and genocide will remain a long-term national and international priority, not a temporary response to Russia’s invasion.
Equally important, the ratification has created a powerful signaling effect. It distinguishes Ukraine not only as a state under attack but also as a norm entrepreneur advancing international criminal justice from within a war zone. Ukraine’s commitment to the ICC during active conflict underscores that accountability and sovereignty can coexist — and indeed, reinforce one another. This has encouraged renewed debate within other conflict-affected states about the political value of ICC membership, potentially reshaping global expectations of how wartime democracies engage with international law.
Michael Kelly, Professor at Creighton University School of Law and The Senator Allen A. Sekt Endowed Chair in Law
The most significant impact so far of Ukraine’s ratification of the Rome Statute is not a particular prosecution; rather it is the larger legitimizing function that draws Ukraine more inextricably into the circle of rule of law nations such as those in the European Union. Fully authoritarian nations such as Russia, China, and Iran stand in stark contrast internationally to democratic rule of nations and Ukraine has shown in its lot with the latter. As the United States shifts more steadily away from the latter to the former, it is unclear how the balance will shift’. Nevertheless, Ukraine is on the right side of history embracing democracy and the rule of law.
David Crane, Founding Chief Prosecutor of the UN Special Court for Sierra Leone and Distinguished Scholar in Residence at Syracuse University College of Law
A year ago, Ukraine's signing of the Rome Statute was a pivotal moment for the country, especially given the ongoing conflict with Russia. By stepping up to this international treaty, Ukraine is taking a clear and firm stand against war crimes and human rights abuses. This commitment not only strengthens its own legal framework for prosecuting those responsible for atrocities but also enhances its credibility in the eyes of the world. As Ukraine’s President Volodymyr Zelenskyy stated, "Our future is in a strong Europe and the world, where human rights and justice prevail." With the backing of the International Criminal Court (ICC), Ukraine can initiate investigations and hold individuals accountable for their actions, even when domestic resources or political will may fall short. This creates a greater capacity for justice and offers much-needed hope to victims who have suffered during the conflict.
On a broader scale, signing the Rome Statute sends an important message to the international community about Ukraine’s dedication to justice and the rule of law. It highlights that, amid war and turmoil, Ukraine is serious about adhering to international norms and values, which can help attract more support from allies who prioritize accountability. This move not only counters the narrative of impunity often seen in conflict zones but also encourages other nations to take a stand against violations. As noted by the ICC's Chief Prosecutor, Karim Khan, “Every crime against humanity affects all of us,” emphasizing the collective responsibility to seek justice. Additionally, by aligning itself with the Rome Statute, Ukraine fosters a sense of stability both regionally and globally as it works to prevent future atrocities and build a resilient democratic identity in a challenging environment.
Chris Goebel, Senior Legal Advisor at PILPG
Further to Paul William’s comments, Ukraine's ratification establishes a new precedent for conflict-affected states seeking ICC membership during active hostilities, potentially fundamentally reshaping international practice around timing and conditions for Rome Statute accession. Historically, states have typically joined the ICC during peacetime or post-conflict transitions when domestic political consensus is usually more achievable and institutional capacity can be methodically developed. Ukraine's decision to ratify while simultaneously prosecuting over 90 domestic war crimes trials, defending against existential military threats, and managing over 200,000 documented potential international crimes changes this traditional sequence. Ukraine’s “ratification under fire” model demonstrates that ICC membership and active conflict are not necessarily mutually exclusive, potentially influencing other conflict-affected countries currently outside the Rome Statute system to consider earlier engagement.
How has ICC membership influenced Ukraine’s domestic justice system and approach to atrocity accountability?
Dr. Paul R. Williams, Rebecca Grazier Professor of Law and International Relations at American University
Ukraine’s ICC membership has accelerated domestic reforms designed to align national law with international criminal standards. In the past year, Ukraine’s parliament has begun harmonizing its criminal code with the definitions of atrocity crimes under the Rome Statute, while judicial and prosecutorial institutions have received enhanced international support to strengthen their investigative capacity. The Office of the Prosecutor General, working with international partners, has institutionalized mechanisms for evidence preservation and case coordination with the ICC. These steps are not only procedural but transformational, building the foundations of a hybrid accountability system that combines international legitimacy with local ownership.
At the same time, ICC membership has reshaped the strategic mindset of Ukraine’s justice sector. Prosecutors and policymakers increasingly frame their efforts through a “complementarity lens” — seeking to demonstrate that Ukraine can credibly investigate and prosecute Rome Statute crimes itself, while relying on the ICC for cases beyond its reach. This has prompted a broader societal conversation about due process, command responsibility, and victim-centered justice. In essence, Ukraine’s engagement with the ICC is catalyzing a deeper maturation of its domestic rule-of-law institutions, embedding accountability as a core pillar of post-war reconstruction and peacebuilding.
Michael Scharf, Co-Founder of the Public International Law & Policy Group (PILPG), former Co-Dean of the Case Western Reserve University School of Law and the Joseph C. Hostetler—BakerHostetler Professor of Law
In October 2024, Ukraine amended its criminal code to bring it in line with the ICC, including adding a new provision on command responsibility (similar to Article 28 of the ICC Statute) which had not previously existed as a mode of liability in Ukrainian law. The concept of command responsibility holds that a superior is responsible for the war crimes committed by subordinates that the superior knew or should have known were being committed and failed to take all necessary and reasonable measures: (1) to prevent the commission of the crimes; (2) to repress the commission of the crimes; or (3) to submit the matter to the competent authorities for investigation and prosecution. Under this type of liability, Ukraine can prosecute military commanders for war crimes committed in their geographic area of command. This will provide Ukraine an important tool in the effective prosecution of Russian war crimes at the command level.
Michael Kelly, Professor at Creighton University School of Law and The Senator Allen A. Sekt Endowed Chair in Law
Ukraine’s constitution federalizes treaty law; consequently, the Rome Statute and the law associated with it come into Ukrainian domestic law. This will prove helpful as Ukraine seeks to prosecute Russian commanders for war crimes, crimes against humanity, and genocide in Ukrainian criminal courts. It may prove especially helpful as the OTP more fully incorporates environmental crimes as a species of war crime into its operations in The Hague. The government in Kyiv wants to prosecute environmental crimes committed by Russia as such.
What opportunities and challenges have emerged in cooperation between Ukraine and the ICC?
Dr. Beth Van Schaack, Senior and Peace Fellow and former Ambassador-at-large for Global Criminal Justice (2022 -2025)
As noted by others on these pages, Ukraine’s ratification of the Rome Statute signals its commitment to pursue justice and accountability for the war crimes, crimes against humanity, and other atrocities being committed daily during Russia’s brutal war of aggression. Ratification further cements Ukraine’s European orientation, particularly given that joining the ICC would be a prerequisite for EU accession. This development also signals a new form of complementarity, a concept that is central to the Rome Statute system. The principle of complementarity dictates that so long as a national court with jurisdiction is appropriately pursuing investigations and prosecutions, ICC actors should stay their hands. It is only when the national court is unwilling or unable to proceed that the ICC should step in. In this regard, the ICC is often called “a court of last resort.”
In the Ukraine context, of course, we have an ICC state party that is eager to pursue justice and, in fact, adjudicating war crimes cases in its national courts in the midst of a hot conflict to a degree unprecedented in human history. There’s no question that Ukrainian courts will continue to be the prime engines of accountability going forward. However, the Office of the Prosecutor General (OPG) has recorded upwards of 200,000 potentially prosecutable crimes since Russia’s full-scale invasion — an impossible juridical task for even the most well-resourced and experienced prosecutorial corps. With the ICC Prosecutor pursuing Russia’s top leadership, including its head of state, Ukraine can focus on direct perpetrators and those down the chain of command. Indeed, the ICC Prosecutor has made clear that his applications for arrest warrants benefited greatly from information sharing and other forms of support from the OPG. As such, we see a new form of “complementarity as cooperation” emerging, whereby the national courts and the ICC undertake a division of labor to manage an enormous crime base.
Michael Scharf, Co-Founder of the Public International Law & Policy Group (PILPG), former Co-Dean of the Case Western Reserve University School of Law and the Joseph C. Hostetler—BakerHostetler Professor of Law
Ukraine’s domestic courts are becoming a laboratory for the refinement of environmental war crimes prosecutions, with the ICC and the rest of the world watching closely. Because Ukraine’s domestic law, like many European countries, provides for trials in absentia, Ukraine is likely to end up prosecuting cases relating to Russia’s environmental war crimes before the ICC has a chance to do so.
In addition, Ukraine’s Criminal Code recognizes the crime of “ecocide,” which may serve as a model for future amendment of the ICC Statute. Article 441 of the Ukraine’s Criminal Code defines ecocide as “mass destruction of flora and fauna, poisoning of air or water resources, and also any other actions that may cause an environmental disaster,” and provides that it “shall be punishable by imprisonment for a term of eight to fifteen years.” In September 2024, Vanuatu, along with Fiji and Samoa, submitted a proposal to the ICC to recognize ecocide as a separate crime on par with genocide and other serious offenses.
Michael Kelly, Professor at Creighton University School of Law and The Senator Allen A. Sekt Endowed Chair in Law
There are now greater opportunities for Ukrainian attorneys to serve as prosecutors, defenders, staff, and even judges of the ICC. Doing so will ensure the benefit of criminal legal practice in Ukraine itself as these individuals over time come home and bring with them their expertise learned in The Hague.
Ambassador (Ret.) Zorica Maric Djordjevic, PILPG Senior Peace Fellow, former Head of the Permanent Mission of Montenegro to the World Trade Organization
Assess opportunities and challenges in cooperation with the ICC and other accountability mechanisms: for Ukraine, signing the Rome Statute opens a crucial legal and moral frontier — institutionalizing accountability amid an ongoing conflict. The ICC’s involvement in investigating war crimes and crimes against humanity in Ukraine builds on precedents from the former Yugoslavia — the International Criminal Tribunal for the former Yugoslavia (ICTY), and later its national courts under the UN guidance, where international mechanisms shaped historical record, but struggled to ensure reconciliation or local ownership. Consequently, the Rome Statute for the states of former Yugoslavia served more as a political and normative anchor than a direct vehicle of justice as the key regional accountability processes were already managed by the ICTY. The opportunity for Ukraine lies in coupling ICC mechanisms with domestic legal reform, hybrid courts, and truth-seeking processes that embed justice into state reconstruction, rather than outsourcing it entirely to international bodies.
The Balkan experience underscores both the promise and the limitation of Rome Statute membership. It provides international legitimacy and deterrence, yet its effectiveness depends on political will, judicial capacity, and societal readiness to confront the past. For Ukraine, learning from post-Yugoslav states means building a system that not only prosecutes crimes, but also transforms justice into a foundation for durable peace, institutional integrity, and reconciliation with the consequences of the war.
How has this step shaped international legal and political discourse on aggression and accountability?
Milena Sterio, Charles R. Emrick Jr. - Calfee Halter & Griswold Professor of Law at Cleveland State University’s Cleveland-Marshall College of Law
Ukraine’s ratification of the ICC Rome Statute has altered the international legal and political discourse on aggression and accountability. Although the ICC already had jurisdiction over the situation in Ukraine in light of dozens of state referrals and the prosecutor’s willingness to open first a preliminary examination and then an investigation, Ukraine’s ratification of the Rome Statute signals the country’s willingness to support the world’s only permanent international criminal court in its pursuit of legal accountability. Although the ICC still lacks jurisdiction over the crime of aggression in Ukraine, the fact that Ukraine, the victim state, has ratified the Rome Statute moves the “goal post” closer, as for the purposes of jurisdiction both the victim and the aggressor state need to be ICC member states; now, in light of Ukraine’s ratification, only the aggressor state (Russia) need become a member (a feat that seems impossible under the current Russian leadership, but that could one day become a reality under a different regime).
In addition, Ukraine’s ratification of the Rome Statute is significant politically, as it places Ukraine within the “club” of member states, which are generally committed to justice and accountability. Thus, by ratifying the Rome Statute, Ukraine has positioned itself well geo-politically and strategically, and has opened the door toward cooperation with other member states. Finally, Ukraine’s ratification of the Rome Statute will bring in line its domestic criminal legislation with current norms and standards of international criminal law, which is a positive development and which once more signals Ukraine’s willingness to support international justice and accountability.
Chris Goebel, Senior Legal Advisor at PILPG
Ukraine’s ratification of the ICC Rome Statute coincided with the formal establishment of the Special Tribunal for the Crime of Aggression against Ukraine through an agreement signed in June 2025 between the Council of Europe and Ukraine. This institutional innovation represents a watershed development in international criminal law: it is the first international criminal tribunal for aggression created outside the UN Security Council framework — thereby circumventing the veto power that has paralyzed UN-based accountability mechanisms. The Special Tribunal’s jurisdiction complements ICC investigations by focusing solely on aggression while the ICC pursues war crimes, crimes against humanity, and genocide. This architectural arrangement — combining the Special Tribunal with Ukraine’s Rome Statute ratification as well as domestic prosecutions — is potentially an important step towards establishing a comprehensive accountability ecosystem in which distinct institutions target different levels of responsibility and categories of atrocity crimes committed in the war.
Looking ahead, what should be the strategic priorities for Ukraine and its partners in consolidating justice mechanisms?
Milena Sterio, Charles R. Emrick Jr. - Calfee Halter & Griswold Professor of Law at Cleveland State University’s Cleveland-Marshall College of Law
Ukraine’s strategic priorities should be to align its domestic criminal law so that there are no gaps or conflicts with respect to the Rome Statute. Once Ukraine has done so, it will be able to fully implement the Rome Statute, and to assume all the relevant duties and responsibilities of a member state.
Michael Kelly, Professor at Creighton University School of Law and The Senator Allen A. Sekt Endowed Chair in Law
One thing the ICC will not be able to embrace is prosecution of Russian corporations for complicity in war crimes committed in Ukraine as the Rome Statute currently only extends the court’s jurisdiction over natural persons - not legal persons. Consequently, Ukraine should prioritize prosecuting Russian corporations for involvement in the war and then request seizure of frozen corporate assets abroad in satisfaction of those judgments. PILPG has white papers on how to accomplish this task.
Chris Goebel, Senior Legal Advisor at PILPG
Ukraine's ratification of the Rome Statute has made Ukraine’s continued capacity-building for war crimes prosecution an important strategic priority. For instance, in addition to aligning its laws with developing ICC standards, Ukraine ought to continue to pioneer integration of environmental harm monitoring into both its prosecutorial and its broader national security framework. With ICC accession, Ukraine has both the opportunity and the obligation to continue to develop sophisticated national expertise in international criminal law, compatible legal procedures, and effective cross-border cooperation — since the ICC expects domestic prosecutions wherever possible.
Dr. Gregory P. Noone, Ph.D., J.D., is the Executive Director, a Senior Peace Fellow, and Senior Legal Advisor for the Public International Law and Policy Group (PILPG)
Three strategic priorities come to mind. First, now that in June 2025 Ukraine and the Council of Europe have agreed to establish a Special Tribunal for the Crime of Aggression, the immediate focus should be on finalizing the staffing, securing funding, and negotiating cooperation agreements. This will close the “aggression gap” at the leadership level and complement the ICC’s jurisdiction, ensuring a coherent international justice architecture. Second, synchronize strategic communications around each major legal milestone (new ICC warrants, tribunal updates, or reparations actions) with targeted sanctions and travel notices, so that accountability carries visible and political consequences. This linkage reinforces deterrence, sustains allied commitment, and demonstrates that justice has tangible costs for perpetrators. Third, prioritize cases against field-grade military officers (Majors, Lieutenant Colonels, and Colonels) who exercise direct control over daily operations and the conduct of troops. These officers serve as the critical link between command intent and battlefield behavior, and are the most likely to travel internationally in the coming years, increasing the practical reach and enforceability of arrest warrants.
Concluding Observations
Ukraine’s first year as a State Party to the Rome Statute has redefined its role in the global justice landscape. The ratification has anchored accountability within Ukraine’s legal and diplomatic identity, transforming ad hoc cooperation with the ICC into a durable institutional partnership. This legal step, taken amid ongoing conflict, has demonstrated that the pursuit of justice need not wait for peace; indeed, it can strengthen both the moral and strategic foundations of peace itself.
Across the contributions gathered here, several themes emerge. Domestically, Ukraine’s ICC membership has catalyzed long-overdue legal reforms, from the incorporation of command responsibility to the development of hybrid accountability mechanisms. Internationally, it has elevated Ukraine’s credibility as a norm-setting state, willing to uphold international criminal law even under fire. The first year of implementation has also revealed both the opportunities and the strains of “complementarity as cooperation,” as Ukraine’s national courts and the ICC together navigate an unprecedented caseload of war crimes.
At the same time, the ratification has reverberated far beyond Ukraine. It has reinvigorated the global conversation on the crime of aggression, coinciding with the June 2025 establishment of the Special Tribunal for the Crime of Aggression against Ukraine. Together, these institutions signal a renewed commitment to closing the impunity gap for leaders who wage unlawful wars.
As this first anniversary passes, Ukraine stands as both a test case and a torchbearer for the future of international criminal justice. Its experience shows that even amid destruction, the deliberate construction of legal institutions can serve as an act of resistance — and a foundation for peace built on law, not force.