Roundtable Blog: One Year Since Ukraine’s Ratification of the Rome Statute

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.

The Slippery Slope of Using Chemical Weapons in Sudan

The Slippery Slope of Using Chemical Weapons in Sudan 

By: Prof. David M. Crane*

The use of gas in a conflict is prohibited under international law and has been for well over a century. Its use is a war crime, plain and simple. Full stop. The use of chemicals against a belligerent in an armed conflict is rare but not unheard of.  It’s been used in the Iraq/Iran war in the 1980s, and the Assad regime in Syria dabbled in its use in the early 21st century. There is also evidence of the use of chemicals by the Russian Federation in Ukraine.

The recent accusations surrounding the alleged use of chlorine gas by the Sudanese army in its conflict with the Rapid Support Forces (RSF) are troubling and must not be ignored. On May 22, 2025, the United States accused the Sudanese military of using chemical weapons. Although they presented no evidence to back their claims, the implications are grave. International law strictly prohibits the use of chemical weapons, and chlorine gas is considered a violation under the Chemical Weapons Convention (CWC), to which Sudan is a signatory.

It's very concerning that chlorine, a substance commonly used in various industries, is reportedly being weaponized. The video evidence documented by the FRANCE 24 Observers team in September 2024, showing barrels dropping from the sky, is particularly alarming. If these claims are substantiated, they mark a dangerous escalation—not just for Sudan but for the principles of international law as a whole.

This pattern—accusations followed by denials from military leaders—is reminiscent of other conflict zones where human rights are disregarded. The Sudanese military’s immediate dismissal of these allegations further obscures the truth and undermines the credibility of international monitoring. The historical context reminds us that the failure to hold violators accountable leads to a dangerous normalization of brutality in warfare. As I’ve previously remarked, “When we allow even the smallest infractions of international law to go unaddressed, we set a precedent that invites further violations.”

The consequences of using chlorine gas as a weapon extend beyond immediate physical harm. They threaten to erode the boundaries that define acceptable conduct in warfare. The very act of using chemical agents introduces a slippery slope, normalizing violence that can lead to more horrific warfare tactics. This hardening stance risks allowing other factions or regimes to follow suit, believing they can operate with impunity.

The international community has a vital role to play right now. It must take these allegations seriously and push for independent investigations into these claims. While the U.S. has made significant assertions, it is essential that any evidence is made public to galvanize an effective global response. The commitment to enforcing the CWC is crucial; violations should prompt not just condemnation but also tangible consequences, such as sanctions or international legal action.

Sudan is at a critical juncture, and what happens next could resonate far beyond its borders. The specter of chemical warfare threatens not only regional stability but also the broader tenets of international law. We can neither afford to turn a blind eye nor allow the unacceptable to become normalized. As a global community, we must remain steadfast in our opposition to the use of chemical weapons, ensuring that those who violate this sacred trust face accountability. It’s not just about Sudan; it’s about the future of warfare and humanity itself.

*Founding Chief Prosecutor, UN Special Court for Sierra Leone; Founder, Global Accountability Network.

Roundtable Blog: Toward Enforceable Security Guarantees

Roundtable Blog: Toward Enforceable Security Guarantees

Editor’s Note:
This post is part of the PILPG Lawyering Justice blog’s roundtable series. Rather than a traditional co-authored piece, it presents a curated set of expert reflections from members of PILPG’s Ukraine Peace Negotiations Working Group. Drawing on the diverse expertise of our Peace Fellows, this roundtable-style blog explores the discussion surrounding security guarantees for Ukraine.  Published under the Lawyering Justice banner, this post reflects our commitment not only to chronicling the legal and diplomatic dimensions of active conflicts, but also to fostering strategic foresight and connecting lawyering to policy planning. We hope this format will serve as a model for future collaborative work on peace and justice.

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In recent months, the question of credible and enforceable security guarantees for Ukraine has become central to its long-term defense and peace architecture. International partners have signaled new commitments—most notably through the Paris declaration of twenty-six states willing to support Ukraine’s security—but the substance and structure of these guarantees remain contested. The strategic landscape is shifting rapidly, and with NATO membership off the table for now, Ukraine and its allies must explore alternative legal and political frameworks capable of deterring further aggression and sustaining peace.

For this Roundtable Blog, we asked the Public International Law & Policy Group’s Ukraine Peace Negotiations Working Group to answer a set of four questions focused on different aspects of the security guarantee debate. Contributors were asked to assess elements of substantive and symbolic security guarantees; alternatives to NATO membership for Ukraine; legal and political frameworks for deploying multinational forces to Ukraine; and the feasibility of providing Ukraine with security guarantees absent Russia’s consent. 

The purpose of this public-facing Roundtable Blog is threefold: to inform Ukrainian policymakers and Peace Formula stakeholders of the legal and strategic variables shaping the security guarantee debate; to connect Ukraine-focused expertise with broader international practice; and to provide analytically grounded perspectives that can guide the development of credible, enforceable guarantees in the months ahead.

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1. Substantive vs. Symbolic Commitments

What concrete elements would distinguish a truly substantive security guarantee for Ukraine from symbolic or rhetorical commitments, and are any states currently moving toward such substance?

Maj. Gen. Darrell Guthrie, Major General (Ret.) U.S. Army Reserve

Security guarantees must be understood as existing along a continuum of credibility. At one end lies the deployment of a robust military presence inside Ukraine—an option that few international partners are currently willing to pursue, but which would send the clearest signal of deterrence. As the continuum shifts outward, forward deployments in neighboring states such as Poland become more politically feasible, though still operationally demanding. Intelligence sharing, while ongoing and valuable, lacks the deterrent force of visible, deployable strength. Aircraft stationed in Germany or the UK may signal intent, but their strategic value increases significantly when positioned closer to Ukraine’s borders—or ideally, within Ukraine itself. Each step away from direct presence becomes increasingly symbolic. In case of using allied planes in Ukraine, partners would need to secure pre-negotiated overflight rights and territorial access agreements. Without these, even well-intentioned guarantees risk being undermined by logistical delays and political hesitation at critical moments.

Ambassador Joachim Rücker, former Special Representative of the UN Secretary-General and Head of the UN Mission in Kosovo

Expectations surrounding troop deployments must remain grounded in political and operational realities. Even under favorable conditions, no more than 40,000 troops from France, the UK, and other partners appear likely to be committed—and only after a ceasefire is in place. German ground deployments remain improbable given current domestic constraints, while all established forms of support from Germany will definitely continue or increase. In any case: what is needed, particularly in the post-ceasefire phase, is an “over-the-horizon” component—an arrangement that allows for quick activation of deterrent forces without immediate escalation. Such a model could offer credible deterrence while remaining politically palatable (the challenge lies in designing mechanisms that can evolve toward substance without overstretching the allies’ capabilities and without triggering premature confrontation). Even with these elements, the guarantees will likely fall somewhere between symbolic and substantive. In this vein, it will also be important to determine first and subsequent responders.

Professor Michael Kelly, The Senator Allen A. Sekt Endowed Chair in Law at Creighton University School of Law

Symbolic deployments can acquire strategic substance through deterrent effect and political signaling. Troops stationed in Ukrainian urban centers under national flags—not NATO—may initially appear symbolic. However, if Russian forces refrain from targeting these areas, the presence gains weight and transforms into a credible deterrent. The perception of risk alters behavior. Recent triggers of NATO’s Article 4, prompted by Russian drone incursions into allied airspace, suggest that the strategic calculus is shifting. These incursions have heightened awareness and urgency across Europe. The timeline matters: by February 2026, Russia will have been fighting Ukrainian democracy longer than Nazi Germany. That historical inflection point should catalyze European leadership and accelerate the transition from rhetorical support to enforceable commitments.

Ambassador Zorica Marić-Djordjević, former Head of the Permanent Mission of Montenegro to the World Trade Organization and Special Representative of Montenegro to the UN Human Rights Council

To transform political declarations into substantive guarantees, four foundational elements are required: legislation, funding, deployments, and treaties. At present, legislative progress among the 26 committed countries remains stalled. Written guarantees with specific operational plans are essential to move beyond symbolism. Europe’s €50 billion Ukraine Facility marks a starting point, but sustained funding and U.S. support remain critical. Deployment discussions are ongoing, yet lack clarity and coordination. Treaty frameworks—whether bilateral or multilateral—must be formalized to provide legal and political weight. Without these pillars, commitments risk remaining rhetorical. The urgency expressed by Ukrainian leadership, including President Zelenskyy’s request for a ten-day window to formalize guarantees, underscores the need to accelerate negotiations and codify intent.

Dr. Paul R. Williams, Rebecca Grazier Professor of Law and International Relations at American University

The central question is whether states are genuinely transitioning from symbolic gestures to enforceable commitments. Frameworks and funding mechanisms have been proposed, and political declarations have been made. Yet the movement toward operational substance remains uneven. The concept of “first responders”—states willing to act immediately in defense of Ukraine—has not been adequately explored. Without clarity on who will act, when, and under what legal authority, the credibility of guarantees remains in question.

Kateryna Kyrychenko, Head of Ukraine Legal Affairs and Program Management Kyiv, Ukraine

Several foundational elements must be resolved before security guarantees can be deemed robust. A temporal gap persists between Ukraine’s expectations and those of its international partners. Ukraine seeks engagement and protection now—not only after a ceasefire. Many so-called guarantees, such as intelligence sharing, do not involve physical deployment. Presence on the ground adds credibility and shifts the perception of commitment. Recent Russian drone incursions have intensified the European security discourse. The strategic environment is evolving rapidly, and guarantees must evolve with it.

2. Deterrence Without Article 5

If NATO membership remains off the table, what combination of bilateral, coalition, or EU-led guarantees could approximate the deterrent effect of Article 5—or is that fundamentally unattainable?

Ambassador Ylber Hysa, former Ambassador of the Republic of Kosovo to Montenegro and North Macedonia

The concept of security guarantees must be disaggregated. NATO membership for Ukraine remains politically blocked, but the broader question is whether NATO itself can still credibly protect its members. Recent Russian provocations—including drone incursions and hybrid operations—challenge the assumption that Article 5 will be automatically triggered. The line between Article 4 (consultations) and Article 5 (collective defense) is increasingly thin, and Russian actions appear designed to test that boundary. These provocations raise doubts about NATO’s internal cohesion and response mechanisms. Security guarantees for Ukraine are not just about Ukraine—they are a strategic investment in NATO’s credibility. If provocations continue, the question becomes: where is the red line, and what would shift the alliance from Article 4 consultations to Article 5 activation?

Sindija Bēta, Legal Officer, PILPG

Past agreements, which focused on consultations, failed Ukraine. The Budapest Memorandum of 1994, which did not deter the events of 2014 nor 2022, demonstrates that non-binding assurances do not prevent aggression. A more viable path could lie in EU membership. The EU Treaty contains a defense and security provision under Article 42(7).  Russia has not objected to EU membership for Ukraine.  Ukraine should aim to anchor its long-term security within the EU framework, where legal obligations and political and economic integration offer a potentially stable foundation. 

Ambassador Joachim Rücker, former Special Representative of the UN Secretary-General and Head of the UN Mission in Kosovo

The EU Treaty offers (in its Article 42,7) a robust foundation for long- and maybe mid-term security guarantees. Nevertheless, in the short term, guarantees must be defined within a clear framework that outlines lines of response and escalation management. Even a symbolic military presence, if politically well coordinated and legally framed, can become substantive. The deterrent effect lies not only in capacity but in clarity of commitment. The EU’s mutual defense clause, while less operationalized than NATO’s Article 5, can serve as a credible basis for coalition-led guarantees in the long-term.

Ambassador Zorica Marić-Djordjević, former Head of the Permanent Mission of Montenegro to the World Trade Organization and Special Representative of Montenegro to the UN Human Rights Council

The most realistic immediate layer of guarantees for Ukraine involves air and missile defenses. These systems are essential to protect civilians, ports, energy infrastructure, and industrial assets from Russian strikes. Expansion of Patriot or similar systems, acceleration of European sky defense initiatives, and integration of early radar warning systems with NATO are critical steps. These measures do not replicate Article 5, but they approximate its deterrent effect by reducing vulnerability and signaling readiness. Ukraine must also strengthen its own military capacity in parallel to ensure sustainability and resilience. The credibility of external guarantees depends not only on what partners provide, but on Ukraine’s ability to absorb, deploy, and maintain those systems over time.

H. E. Dr. Igor Luksic, the former Prime Minister of Montenegro

Security guarantees very much depend on the context and need to be seen as part of a comprehensive approach to ending of the current war. In order to define appropriate security guarantees (related to the present and the future), it is important to understand what is the treatment of the currently invaded territories. Whenever the peace agreement is reached, the Ukrainian security in general will be inextricable from the law enforcement in that region, as well as its economic stabilization and development. To that end, it is important to closely monitor what happens and if anything happens at all with regard to the Gaza Strip and the so-called GITA idea, as it appears to have the possibility to become a kind of model to, with necessary adaptation, use it in similar cases. Additionally, it is hard to imagine any model reached without the eventual mandate of the UN Security Council. In my view, it may be of interest to also take a look at the status of the Trusteeship Council, as it still formally exists and is stipulated by the UN Charter. Contrary to its original role, in this case, it may provide a legal framework for the period between the peace agreement and, hopefully, eventual EU membership of Ukraine.

3. Legal and Political Frameworks for Deployment

What legal or political frameworks could authorize the forward deployment of multinational forces into Ukraine—whether as trainers, peacekeepers, or deterrent forces—before a ceasefire is reached?

Maj. Gen. Darrell Guthrie, Major General (Ret.) U.S. Army Reserve

Authorization frameworks must be grounded in sustainability. Forward deployment before a ceasefire remains politically sensitive, but the question of long-term viability is paramount. Ukraine receives a wide array of weapons systems, yet the sustainability model remains unclear. Battlefield damage, logistical strain, and replenishment cycles require structured planning. Air and missile defense systems are critical, but must be embedded within a broader framework that supports Ukraine’s ability to defend itself over time. Ukraine possesses a manufacturing base capable of supporting such efforts, but coordination is essential. The U.S. continues to work on artillery ammunition commitments, signaling intent but also revealing delays. Structured deployments—whether trainers, peacekeepers, or deterrent forces—must be framed as part of a multi-year commitment, not subject to shifting political winds. Legal frameworks must reflect that continuity.

Kateryna Kyrychenko, Head of Ukraine Legal Affairs and Program Management Kyiv, Ukraine

Hesitation among international partners to authorize forward deployment before a ceasefire is understandable, but alternative forms of guarantees already exist. Sanction-based guarantees, for example, offer conditional leverage. Presence on the ground, even in non-combat roles, introduces risks of escalation and political backlash. The deterrent effect of such deployments depends not only on legal authorization but on strategic signaling. For many partners, the possibility of direct confrontation with Russia remains the primary deterrent. Engagement levels vary across states and will likely evolve in phases. Legal frameworks must accommodate differentiated participation and phased escalation, allowing some states to engage earlier through training missions or monitoring roles, while others commit to deterrent deployments post-ceasefire.

Ambassador Zorica Marić-Djordjević, former Head of the Permanent Mission of Montenegro to the World Trade Organization and Special Representative of Montenegro to the UN Human Rights Council

The next step in operationalizing guarantees lies in predictable, multi-year military funding. The EU and U.S. must pass and adopt aid packages that guarantee supply chains and defense capabilities over time. Without sustained funding, deployments risk becoming episodic and politically vulnerable. To deter Russia from exploiting a ceasefire, rapid response commitments must be formalized—drawing lessons from Bosnia’s Berlin Plus post-conflict arrangements. Legal frameworks should enable pre-authorized activation of multinational forces in response to violations or provocations, rather than relying on ad hoc political consensus. Forward deployment, even in limited roles, must be embedded within a broader architecture of readiness, deterrence, and legal clarity.

Professor Michael Kelly, The Senator Allen A. Sekt Endowed Chair in Law at Creighton University School of Law

Historical precedent offers guidance. In the 1990s and early 2000s, the UN framework was used to authorize multinational action—sometimes directly, sometimes through creative interpretation. The first Iraq war relied on explicit Security Council resolutions; the second manipulated existing mandates. Today, the challenge lies in Russia’s veto power. Any Security Council initiative must navigate that obstacle. Yet precedent shows that legal creativity, coupled with political will, can produce frameworks that authorize action even in contested environments.

4. The Role of Russia

Is it possible to design security guarantees for Ukraine that are effective and enforceable without Russian consent, or does any durable arrangement inevitably require Moscow’s participation or at least acquiescence?

Ambassador Joachim Rücker, former Special Representative of the UN Secretary-General and Head of the UN Mission in Kosovo

This question increasingly guides strategic discussions in capitals such as Rome and Berlin. A growing chorus of foreign observers argues that without Russian consent, any forward-looking security guarantees lack realism. This view, however, risks eventually delaying the deployment of ground forces and discouraging the 26 states currently engaged (which include Italy and Germany). The absence of Russian acquiescence becomes a political constraint, not just a legal one. But the UN Security Council remains a potential avenue. Despite the risk of a Russian veto, the Council offers a framework that brings Moscow to the table—even if only procedurally. Recent remarks by President Trump, which reaffirm the UN’s relevance while criticizing its effectiveness, create a tactical opening. That momentum should be harnessed. Rather than abandoning the UN, efforts should double or triple there in order to draft, discuss and secure a resolution that legitimizes a coalition-led guarantee. The presence of Russia, even as an obstructive actor, may paradoxically strengthen the legal and diplomatic foundation of the initiative.

Dr. Paul R. Williams, Rebecca Grazier Professor of Law and International Relations at American University

Diverging opinions persist within the EU on whether Russian consent is a prerequisite. Some argue that engaging Moscow too early risks derailing the coalition’s internal consensus. Others believe that any durable arrangement must eventually confront the question of Russian acquiescence. The sequencing of engagement matters. Can the 26 build a coherent proposal before involving Russia? And what legal instruments would underpin such a coalition? A signed memorandum? A UN resolution? A treaty-based framework? These questions remain unresolved, but they are central to the credibility of any future guarantee.

Ambassador Elayne Whyte Gomez, Senior Fellow of the UN Institute for Disarmament Research, Professor at Johns Hopkins School of Advanced International Studies, and former Ambassador and Permanent Representative of Costa Rica to the United Nations

The role of Russia must be addressed, but not prematurely. Discussing Russian involvement too early risks freezing progress among Ukraine’s partners. A phased approach may be more effective: first, build a solid proposal among the 26; then, engage Moscow with a unified front. The legal basis for a coalition of the willing must be clarified. Article 51 of the UN Charter—Ukraine’s right to self-defense—offers a foundational framework. Beyond that, the UN General Assembly, while not legally binding, provides a strategic theater to challenge prevailing narratives and build diplomatic momentum. The distinction between UNGA and UNSC pathways must be understood not only in legal terms but in political signaling.

Ambassador Ylber Hysa, former Ambassador of the Republic of Kosovo to Montenegro and North Macedonia

The essential debate is not whether the UN is good or bad—it is whether the UN is viable under current conditions. As it stands, Russian consent appears unlikely. The UN Security Council is not a realistic avenue in the near term. Alternatives must be explored. What can be done without Russian participation? What legal instruments exist outside the UN framework? Three tracks should be pursued in parallel: one through the UN, one without Russian consent, and one with Russian consent if conditions change. Each track must be developed with contingency planning and legal rigor.

Ambassador Zorica Marić-Djordjević, former Head of the Permanent Mission of Montenegro to the World Trade Organization and Special Representative of Montenegro to the UN Human Rights Council

Russia’s position is clear and vocal. Foreign troops and NATO-style guarantees on Ukrainian territory are red lines. Any coalition of the willing must be framed carefully. Several legal bases exist. First, Article 51 of the UN Charter allows Ukraine to invite other states to assist in its defense—this is already the foundation for current Western training and aid missions. Second, treaty or political commitments can formalize bilateral or multilateral guarantees. Third, EU and NATO instruments—such as Berlin Plus—offer operational models, as seen in post-Bosnia deployments. These frameworks do not require Russian consent but must be designed to withstand political and legal scrutiny.

President Zelenskyy's Three Pillars: Envisioning Security Guarantees for Ukraine

President Zelenskyy's Three Pillars: Envisioning Security Guarantees for Ukraine

By: Sindija Beta, Paula C. Kates, and Dr. Paul R. Williams

As the Russian war of aggression against Ukraine rages on and talk of peace negotiations continue, the key issue is no longer territory—but rather, “security guarantees.” Since the full-scale invasion in 2022, Ukrainian, European, and US officials have struggled to define what this term means in practice. The Trump-Putin Summit in Alaska, the subsequent Ukraine–US–EU–NATO leaders’ meeting in Washington, D.C., and the high-level Coalition of the Willing meeting in Paris have only intensified the conversation. More recently, according to statements emerging from the latest Coalition of the Willing meeting, all or parts of the security guarantees Ukraine’s allies would provide to Ukraine have already been developed. These, however, are kept highly confidential for the time being. 

Ideally, Ukraine would join NATO, gain full protection under Article 5 of the North Atlantic Treaty, and Russia would never again threaten its security and territorial integrity. This is not an unreasonable aspiration. Article 5—the principle that an attack on one is an attack on all—combined with the deployment of the Alliance’s forces along NATO's eastern border, has deterred Russian imperialism for decades. No NATO member has suffered a kinetic attack from Moscow, despite the fact that several share borders with Russia and have long histories of being targeted by the Kremlin.

Practically, this scenario would entail pushing Russia’s forces out of Ukraine’s territory, obtaining the unanimous support of all existing NATO member states, and likely deploying NATO troops to Ukraine as part of the alliance’s eastern posture. For now, this remains out of reach.

The most recent discussions, particularly surrounding the meaning of “Article-5 like guarantees” and “security guarantees,” are discussed in another PILPG blog post. This current post builds on that discussion by focusing on the security guarantees framework outlined by President Volodymyr Zelenskyy in August 2025 and the realities with which that framework will have to contend. President Zelenskyy outlined three pillars: funding for Ukraine’s military, mutual defense agreements with NATO member states, and sanctions against Russia. 

The First Pillar: Developing and Funding Ukraine’s Military and Domestic Defense Industry

The first pillar is arguably already in advanced stages and, according to President Zelenskyy, will form the “central element of security guarantees”. President Zelenskyy defined this pillar as a three-track system: domestic production of drones and technology, European output of artillery and air defenses, and American supply of advanced weapons. Ukraine’s drone production and increasing development of robotic systems utilized in the war have been highly successful. Ukraine’s output of drones rose to several hundred thousand per year, including 15,000 ground robots, in 2025. Ukraine has also begun developing its own long-range missiles domestically and has successfully deployed drones in surveillance, attacks, and mine laying and demining. These advancements have been essential in counter-balancing Russia’s manpower advantage.

The goal is for Ukraine to obtain self-sufficiency in its weapons production.  In 2023 and 2024, Ukraine concluded a series of bilateral security agreements with various partners, including the United Kingdom, the United States, France, and Germany. The agreements provide for a multiple-year commitment to provide military and financial aid to Ukraine and ongoing training support to ensure Ukraine’s military interoperability with NATO structures. Following a meeting of the Coalition of the Willing on September 4, 2025, to discuss security guarantees, President Emmanuel Macron of France affirmed the Coalition’s support for the development of a strong Ukrainian military.

However, weapons support from other states is often subject to domestic political pressures, as seen recently in the Trump Administration’s decision to end weapons donations to Ukraine. While currently NATO and European states are filling the gap by purchasing American weapons and passing those on to Ukraine, the most sustainable approach is for Ukraine to build up its own domestic defense industry—though whether or not Ukraine (and European states sponsoring this effort) have the financial resources to accomplish this remains unclear.

The Second Pillar: Mutual Defense Agreements with NATO Member States

The second pillar, mutual defense agreements with NATO member states, is still contentious, as discussed in the prior post. Current bilateral agreements merely require consultations within 24 hours of any new attack, but Ukraine seeks language that goes further, obligating partners to take concrete action in defense of Ukraine in the event of renewed aggression.

What is apparently currently on offer, however, is unlikely to form a NATO-style guarantee. Instead, the emerging model is best described as “collective response without automaticity.” Partners are pledging coordination and rapid assistance, but not a binding commitment to use military force in defense of Ukraine. This reflects deep political caution: neither Washington nor major European capitals are prepared to risk a direct confrontation with Russia by entering into a treaty with Ukraine that requires them to go to war with Russia in the event Russia attacks Ukraine again.

Related to this is the development of a proposal for a so-called “reassurance force” which would see European troops on the ground in Ukraine. This effort is part of the Coalition of the Willing’s efforts, led by the United Kingdom and France. Although the precise contours and size of such troop deployment are confidential, in early September, President Macron declared the plans complete. 

According to President Macron, 26 states will take part in the reassurance force and the force will serve on land, in the sea, and in the air. President Zelenskyy further clarified that these states will participate in different forms depending on their capabilities, which will include cyber and air defense.  A number of states had already prior expressed readiness to contribute troops to help provide security for Ukraine. 

While few specifics are currently public, commentators have noted that these plans could include the deployment of troops from mainly European states in strategic locations, such as in Odessa and Kyiv and patrolling the Black Sea, as well as the provision of air defense, air patrolling, surveillance, intelligence, logistics, and training units. The US is expected to provide logistics, intelligence, and possibly air defense support, with its assets based outside of Ukraine, to defend against Russian drones and missiles. Talks with the US about its role within the Coalition of the Willing are continuing. As such a deployment would require a joint control and command structure, NATO's existing infrastructure could be utilized, along with its joint intelligence, surveillance, and reconnaissance capabilities. Nevertheless, NATO Secretary General Mark Rutte has said that, although being part of the Coalition of the Willing talks, NATO will not have a role in these security guarantees.

An overarching issue is that the US and European states are deeply reluctant to provide the type of guarantees that might actually lead to a military conflict with Russia. For this reason, some emphasize that any deployment of troops can only happen once there is a ceasefire or a peace agreement in place. This may, however, incentivize Russia to continue fighting to ensure that no foreign troops can be deployed in Ukraine. 

Alongside the need for a ceasefire or peace agreement for any reassurance force to deploy, commentators continue to discuss the extent to which Russia would “allow” these security guarantees. In theory, security guarantees mean binding commitments from Western states to act should Russia attack Ukraine again, or mechanisms to support Ukraine in deterring Russia from further attacks, such as a tripwire force. These are measures that are exclusively the competence of Ukraine and its allies. Russia should have no say in these. When it comes to peacekeeping or monitoring forces deployed on the line of contact between Russian and Ukrainian forces, some degree of Russian buy-in is required as Russia would have to agree to respect, and not attack, those peacekeeping forces. In practice, the discussion around security guarantees seems to blend both of these measures together, thereby inadvertently giving Russia a veto over any security guarantees that could be implemented.  

The Third Pillar: Further Economic Sanctions Against Russia

The third pillar shifts the focus from military force to economic leverage. Deterrence is not only about tanks and missiles; it is also about signaling to Moscow that renewed aggression will trigger immediate and severe financial consequences.

Since Russia’s full-scale invasion of Ukraine in 2022, the US, the UK, the EU, and other countries have imposed multiple rounds of sanctions on Russia.  Targets have included Russian foreign reserves, Russian banks, the Russian defense industry, as well as individual oligarchs. The Trump Administration has frequently dangled the threat of further sanctions if Russia does not enter negotiations to end the war. Thus far, however, President Trump has allowed every supposed-deadline to pass by without imposing the threatened punishment. The efficacy of imposed sanctions is also often debated; President Putin claims that the Russian economy has not suffered from them, and Russia has been able to skirt some of them, particularly in its ongoing sales of oil and gas to China, India, and European Union states, as well as sales via its shadow fleet. It remains to be seen how the effect of sanctions will play out in the long run, and whether further sanctions would succeed in applying a decisive amount of pressure. 

As part of the existing sanctions regime, there are a significant number of frozen Russian assets. Ukraine is seeking the full confiscation of Russia’s assets to be used for Ukraine’s reconstruction. While European states have to date been reluctant to confiscate all of Russia's frozen assets, they have begun using the interest generated from investing the assets to provide Ukraine with aid. The European Union’s foreign affairs chief Kaja Kallas has also recently stated that frozen assets will only be returned to Russia if it pays reparations to Ukraine. The confiscation, and potential repatriation of those assets to Ukraine, plays an important role in Ukraine’s future security framework. As noted above, financial constraints are a key limiting factor in Ukraine’s ability to develop its own domestic defense production and continue procuring weapons systems from Europe and the US. An influx of additional financial resources, such as the significant amount currently frozen around the globe, would assist with Ukraine’s efforts to become self-sufficient.

Conclusion

As leaders around the world debate what role their states will play in any reassurance force and security guarantees for Ukraine more broadly, an outline of what those security guarantees may look like has begun to emerge. President Zelenskyy’s three pillar framework identifies a Ukraine-first approach, bolstered by commitments from Ukraine’s allies to come to Ukraine’s aid militarily and financially to prevent further Russian expansionism. By putting Ukraine’s own capacities as the first and main pillar, Ukraine’s security guarantees account for the constraints of its allies while ensuring that it is able to defend itself should Russia again threaten its sovereignty and territorial integrity. 

“Security Guarantees” for Ukraine: Breathing Life into a Buzzword

“Security Guarantees” for Ukraine: Breathing Life into a Buzzword

By: Paula C. Kates, Sindija Beta & Dr. Paul R. Williams

The purpose of this blog is to explain what is meant by the now frequently used term “security guarantees” in the context of Russia’s war of aggression against Ukraine.

Following President Donald Trump’s meeting with Vladimir Putin in Alaska on August 15, 2025, and his subsequent meeting with President Volodymyr Zelenskyy and several European leaders in Washington, D.C., on August 18, 2025, a renewed focus has emerged on the question of “security guarantees” for Ukraine.  

The phrase “security guarantees” is an often used buzzword, which few diplomats, commentators and even experts seem to understand.   

This blog explores the multiple dimensions of the term “security guarantees,” including:  What does the term “security guarantees” traditionally mean? What constitutes an Article 5-like guarantee? Which states or organizations might implement such guarantees? Does an Article 5-like guarantee require the deployment of combat troops on the ground in Ukraine? What options exist for configuring combat forces—or other types of security forces—on Ukrainian territory? How might these forces operate in the absence of an Article 5-like commitment? And finally, what binding obligations or discretionary measures might apply to—or be available to—the United States?” 

What does the term “security guarantees” traditionally mean?

There is no universally accepted definition of the term “security guarantees.” Some argue that a true “guarantee” of security is impossible and prefer the term “security commitment” to reflect the reality that no state can fully ensure the security of another. Nonetheless, in common discourse, security guarantees are generally understood as commitments to safeguard and maintain the status and territorial integrity of a specific state or entity against external aggression. These guarantees may be extended by individual states, groups of states, or international organizations.

For instance, the Mutual Defense Treaty Between the United States and the Republic of Korea of 1953, commits the United States to come to South Korea’s defense in the event of external aggression. Since its signing, the United States has provided extensive defense support and has maintained a military presence in South Korea as a deterrent. Notably, the Treaty also extended the U.S. “nuclear umbrella” to the Republic of Korea, meaning that the deterrent effect of U.S. nuclear weapons applies not only to threats against the United States itself but also to those targeting South Korea.

An example of a multilateral security guarantee is the European Union member states’ commitment enshrined in Article 42(7) of the Treaty on European Union. Under the Article, member states are obliged to provide “aid and assistance by all the means in their power” to any other member state that is the victim of armed aggression on its territory. What distinguishes this clause from that of the United States and Korea Agreement is that, as the European Union is not a military institution, “all the means in their power” does not necessarily mean using armed force and may instead refer to non-military measures such as sanctions, economic assistance, diplomatic pressure, cyber defense support, or logistical coordination.

What constitutes an Article 5-like guarantee? 

The notion of an Article 5-like guarantee has its origins in Article 5 of the North Atlantic Treaty.  Article 5 provides that “an armed attack against one or more [member states] in Europe or North America shall be considered an attack against them all and consequently they agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defense … will assist the Party or Parties so attacked.”  Put simply, Article 5 legally binds all NATO members to come to the aid of any single NATO member state that is attacked.  

Article-5 like guarantees for Ukraine were proposed during the Istanbul talks of March 2022 where it was suggested that, in lieu of full NATO membership, a coalition of willing states could provide a collective security guarantee akin to that provided by Article 5.  Russia counterproposed with the insistence that it be one of the guarantor states with a veto power over any support that may be provided should Ukraine again become a victim of armed aggression. 

In March of 2025, Italian Prime Minister Giorgia Meloni floated a similar proposal for Article 5-like guarantees. Contemporaneous commentary indicated that the Prime Minister intended for NATO and its member states to provide the collective security guarantee; but since Ukraine would not be a member state it could not be termed an Article 5 guarantee, and thus must be called an Article 5-like guarantee. At the time, Prime Minister Meloni reportedly envisioned that no NATO member state would necessarily need to station combat troops in Ukraine, as such an approach would be more acceptable to Russia. 

Following the recent summit between European leaders and President Trump in Washington, new details emerged regarding Italy’s evolving proposal on security guarantees. According to reports, the Italian government circulated a more formal draft to summit participants, outlining a collective assistance mechanism as an alternative to NATO membership. The plan would commit nations with bilateral agreements with Ukraine to swiftly coordinate a response in the event of an attack, potentially within 24 hours, though some countries have suggested timelines ranging from 12 to 72 hours. 

Proposed measures include rapid and sustained defensive support for Kyiv, economic aid, military reinforcement, and sanctions against Russia. While it remains unclear whether European troops would be deployed on Ukrainian soil, sources indicate that the framework could mirror the 2024 Rome-Kyiv bilateral pact. The reaction force might involve all NATO members, a subset, or even interested non-members like Japan and Australia. Crucially, any immediate response would rely on NATO’s existing infrastructure. Should Moscow launch an attack against Ukraine, a consultative process among guarantors would determine a proportionate—military or economic—reaction. 

While Italian Prime Minister Giorgia Meloni has notably distanced herself from the Coalition of the Willing initiative, particularly regarding proposals that involve deploying European troops to Ukraine, recently Italian Minister of Defense, Crosetto, clarified that this proposal is not mutually exclusive with the “Coalition of the Willing” concept, and both approaches could coexist.

What kinetic or other action could be taken under an Article 5-like guarantee?

At its core, an Article 5-like guarantee implies the potential for a military response to defend Ukraine in the event of renewed aggression. This could involve direct deployment of combat forces or the use of military capabilities to repel an attack. However, recent discussions—particularly among European states—have signaled growing interest in a broader spectrum of responses that fall short of direct military engagement.

One such alternative involves robust and sustained financial and arms commitments that enable Ukraine to maintain a level of military capability sufficient to deter future aggression on its own. This approach would avoid the need to deploy guarantor states’ militaries, but would require a significant and ongoing flow of weapons, ammunition, and funding. As war fatigue sets in across Europe and political support in the United States continues to erode, the prospects for maintaining such high levels of assistance are increasingly uncertain.

Moreover, a security guarantee structured solely around arms and financing—without the credible threat of direct military response—would only marginally exceed the support already provided to Ukraine by its allies to date. As a result, the credibility and deterrent power of such a guarantee may be limited unless paired with explicit political commitments or the credible presence of forward-deployed forces.

Which states or organizations might implement such guarantees? 

More recently the Article 5-like guarantee has evolved from a guarantee by NATO to a guarantee by a so-called "Coalition of the Willing"willing to participate in an ad hoc security arrangement. France and the United Kingdom have indicated a willingness to participate in such a coalition and to possibly deploy combat troops to Ukraine, though to limited geographic areas.  Germany and Poland have also indicated a willingness to provide these Article 5-like guarantees as part of a coalition, but would not station combat troops in Ukraine. Other states, including several European states, Japan, New Zealand, and Australia, have expressed interest in the Coalition of the Willing but have not provided a definite position on what could be their involvement. 

Notably, after the European meeting with President Trump on August 18, 2025 NATO Secretary General Mark Rutte seemed to resurrect the idea that the Article 5-like guarantees would be provided by NATO.

President Trump has indicated that he, and even President Putin, are open to Article 5-like guarantees, though it does not appear that either one of them envision the United States itself providing such a guarantee.  

Importantly, without a commitment from the United States for significant American involvement, any attempt at “Article-5 like” security guarantees may fall far short of what is guaranteed by Article 5 given the limited military infrastructure of the other NATO member states.

While there has been some discussion that nonaligned states could play a role in providing security guarantees or act as a peacekeeping force either under a United Nations mandate or another mechanism, to date, there has been little development and interest in turning the discussion into practical measures. When it comes to mandating such a force by the United Nations, Russia’s role as a permanent member state of the UN Security Council makes the debate unfeasible due to well-founded concerns over Russia’s interests in manipulating the mandate of a UN peacekeeping force and the power to subsequently withdraw the force prematurely to suit its political interests. 

Does an Article 5-like guarantee require the deployment of combat troops on the ground in Ukraine? 

Under the Italian proposal, it would not be necessary to deploy troops in order to guarantee Ukraine’s security. The concept relies instead on the deterrent effect of a credible threat—the potential use of force by NATO or a coalition of the willing—as sufficient to prevent future Russian aggression.

More recent proposals, however, envision a stronger form of deterrence that combines an Article 5-like guarantee with the deployment of some kind of military force away from the frontlines as additional support to the Ukrainian military, and possibly U.S. air support. The specific configuration of such forces is discussed in greater detail below.

What options exist for configuring combat forces—or other types of security forces—on Ukrainian territory? 

British officials have indicated readiness to place British troops in Ukraine, as have Belgium, Lithuania, and Estonia. On the other end of the spectrum are Poland, Germany, and Hungary, all of which have firmly declined the option of placing their troops in Ukraine. The United States has also dismissed the deployment of American troops inside Ukraine.

Troops that would be deployed could be done so in multiple configurations. 

Enforcement force: An initial, but now seldom discussed, option involves deploying a fully militarized peacekeeping force along the line of control between Russia and Ukraine. This force would be tasked with monitoring compliance, maintaining separation, and potentially responding to violations, much like traditional enforcement missions.  

Reassurance force:  A more frequently discussed configuration envisions forces providing air cover over western Ukraine, conducting demining operations in the Black Sea, and protecting key ports and airfields. These efforts would be paired with ongoing training and advisory support to the Ukrainian military, enhancing both operational readiness and public confidence in Ukraine’s defense posture.

Deterrent or “Tripwire” force: Under this model, a smaller number of international troops would be positioned in strategically significant areas to serve as a deterrent “tripwire.” The logic is that any attack resulting in non-Ukrainian casualties could trigger a military or other forceful response from coalition member states—thereby raising the political and operational cost of aggression.

U.S. Role and Requirements: European states have made clear that both the reassurance and tripwire models would require two key forms of U.S. support: (1) logistical, lift, intelligence, and munitions assistance; and (2) “over-the-horizon” combat support. Notably, President Trump has yet to clearly articulate the role he envisions for the United States in any such arrangements, although he has hinted at a potential willingness to provide air support.  

Other lighter footprint options occasionally discussed include a monitoring force and/or a training force. A monitoring force would consist of a small number of on-the-ground personnel tasked with observing and reporting potential violations of a peace agreement. In theory, such a force could play a critical role in verifying substantial breaches of the agreement and, in doing so, could trigger a military or other form of response from coalition of the willing member states. 

The lightest form of on-the-ground involvement would consist of a limited number of personnel tasked with providing ongoing training to the Ukrainian military and assisting in the strengthening of Ukraine’s defense systems. This model could share features with a tripwire force by effectively embedding non-Ukrainian military staff within Ukrainian units—creating a scenario in which any attack on Ukrainian forces could endanger foreign personnel. Such a configuration, while limited in scope, could still serve as a meaningful deterrent by raising the stakes of Russian aggression.

How might these forces operate in the absence of an Article 5-like commitment? 

Importantly, it is not necessary to establish an explicit Article 5-like security guarantee in order to deploy troops to Ukraine from member states of a coalition of the willing. In particular, forces deployed in roles such as tripwire, monitoring, or training missions could still serve a significant deterrent function. If these personnel were to be targeted by Russia, the political and strategic consequences would likely be severe, potentially triggering a strong collective response—even absent a formal mutual defense commitment. The mere presence of such troops, especially from NATO or EU member states, may thus serve as a powerful signal of resolve and solidarity with Ukraine.

What binding obligations or discretionary measures might apply to—or be available to—the United States?

Some commentators have suggested that a coalition of the willing—composed in part of NATO member states—could serve as a backdoor mechanism for securing U.S. security guarantees. The logic behind this view is that if a NATO member state, acting within such a coalition, undertakes military action in defense of Ukraine and is subsequently attacked by Russia, this could trigger Article 5 of the NATO Treaty, obligating the United States and other NATO members to respond. However, it remains unclear whether the United States views such a scenario in the same light, or whether it would interpret an attack on a coalition-based deployment as meeting the threshold for collective defense under NATO’s legal framework.

Security Guarantees - the Russian perspective

While Western states may be debating how to make sure the security guarantees truly prevent the resumption of a renewed aggression some years after signing the peace agreement, the Russian perspective on the conversation is noticeably different. After the August 2025 meetings, reports celebrated the fact that Putin had allegedly agreed to security guarantees for Russia. What was missing from the celebration was that, for Russia, security guarantees mean no NATO or European troops in Ukraine and a veto for Russia on any assistance that could be provided to Ukraine in the event of a new war. This, as noted above, is what already created an impasse at Istanbul in 2022. 

Why are security guarantees so important?

Security guarantees are crucial to any peace deal because of Russia’s history of violating ceasefires and peace agreements. To take one example, during the 2008 Russo-Georgia War Russia invaded the Georgian regions of Abkhazia and South Ossetia. A ceasefire was brokered, but immediately broken by Russia when it refused to withdraw its troops from the Georgian regions. Ukraine has itself faced numerous broken agreements with Russia. In 1994, Ukraine entered into the Budapest Memorandum in which, among other things, Russia committed to recognizing Ukraine’s independence, sovereignty, and borders—and to guard against any foreign intervention.  This guarantee failed. Similarly, in the wake of Russia’s 2014 aggression against Ukraine it entered into the Minsk Protocols, which Russia also violated. Based on this history, Ukraine is adamant that serious security guarantees are necessary in order for there to be any substance to a peace agreement with Russia.

Conclusion

The evolving discourse around “security guarantees” for Ukraine reflects both the urgency of Ukraine’s need for credible protection and the complexity of delivering such protection in the current geopolitical environment. As the concept moves from rhetorical aspiration to operational planning, the range of proposed guarantees—from formal Article 5-like commitments to more flexible coalitions of the willing, and from fully deployed combat forces to lighter tripwire and training missions—demonstrates the varied levels of risk, resolve, and resources that different states are willing to assume.

Ultimately, the credibility of any security guarantee for Ukraine will depend less on the terminology used and more on the political will behind it, the clarity of its implementation mechanisms, and the strategic signals it sends to both allies and adversaries. Whether through direct deployment, sustained arms support, or embedded international personnel, the international community must now translate the concept of “security guarantees” into practical and enduring measures that both deter further aggression and support Ukraine’s long-term sovereignty and stability.