From left, Ukrainian President Volodymyr Zelenskyy, Britain Prime Minister Keir Starmer, French President Emmanuel Macron and German Chancellor Friedrich Merz leave a meeting on Dec. 8, 2025, at 10 Downing Street in London. (AP/Kin Cheung)
The Conversation
Efforts to end the war in Ukraine have grabbed global attention, fueled by debates over U.S. President Donald Trump's 28-point plan – which many analysts see as favoring Russia – and European attempts to craft a counterproposal.
We've been here before. Failed attempts to end the conflict date back to the beginning, soon after Russia's 2014 occupation of Crimea and parts of the Donbas. After Russia's full-scale invasion in February 2022, peace discussions started up again within days, and they have continued in fits and starts since.
Prospects for a lasting peace remain dubious. One reason, I believe, is that the proposals pay little attention to the relationship between peace and justice – a flaw shared by previous plans.
Is peace worth having if it's unjust? Is justice worth pursuing if it prolongs war? Those are questions as troubling as they are old. "Peace is the effect of justice," as St. Thomas Aquinas argued in the 13th century. Ceasefires built on coercion or exhaustion inevitably fail because they do not resolve the conflict's causes.
Aquinas is a major figure in the just war tradition, the focus of my research. This area of ethics helps weigh when war is justified – and also how it should end.
Today, the insight that peace and justice are inseparable grounds what international law terms "transitional justice." By focusing on victims and assuring accountability for past wrongs, this approach seeks to disrupt recurring cycles of violence.
Past agreements and proposals aimed at ending the conflict in Ukraine failed because in the rush to stop the fighting, they ignored questions of justice. The literature on transitional justice, by contrast, encourages negotiators to attend to four interdependent principles: truth, justice, reparations and safeguards against future recurrence.
1. Truth
Truth is essential for peace. As St. Augustine, one of the earliest Christian just-war thinkers, put it in the fourth century, "false justice" arises when the pursuit of truth is abandoned.
Durable peace agreements require all sides to cooperate with international efforts to document war crimes and human rights violations, such as the United Nations' Independent International Commission of Inquiry on Ukraine. This is no small task. So far, Ukraine has granted access to outside investigators, but Russia has refused, even when it has accused Ukraine of war crimes.
But reconciliation requires a complete accounting of the harms done. Archbishop Desmond Tutu, who headed South Africa's Truth and Reconciliation Commission after the end of apartheid, explained that "forgiveness depends on repentance, which has to be based on an acknowledgment of what was done wrong, and therefore on disclosure of the truth."
Truth-telling also prevents false narratives from creating "justifications" for renewed fighting. Thus, peace in Ukraine will require a global effort to combat disinformation legitimizing Russia's aggression and obscuring its war crimes.
A mother cries at the coffin of her son, Oleh Borovyk, a Ukrainian serviceman, during his funeral in Boiarka, Ukraine, on Dec. 3, 2025. (AP/Evgeniy Maloletka)
2. Justice
Justice demands holding perpetrators to account. If, as Aquinas argued, a just war is "one that avenges wrongs" or seeks "to restore what [has been] seized unjustly," ignoring these concerns when ending a war would itself be unjust.
Treating collaborators with fairness requires nuance. In some cases, pardoning individuals who acted under duress – and even willing but nonviolent collaborators who fully disclose their actions – can support postwar reconciliation. Especially in areas once occupied by enemy forces, frank confessions can help rebuild social trust.
However, amnesty for war crimes and crimes against humanity is impermissible because pardons deny victims justice and may embolden future perpetrators. The International Criminal Court has issued arrest warrants for six Russian officials, including President Vladimir Putin. Meanwhile, the Council of Europe has established a Special Tribunal for the Crime of Aggression Against Ukraine, which would prosecute senior Russian officials who ordered the illegal invasion.
Realistically, neither forum can try those responsible without either Russia's defeat or Putin's removal from power. But in the interim, other countries can continue to support Ukrainian courts handling war crimes cases.
Justice also requires holding one's own side accountable, even if the other side will not reciprocate. Allegations of war crimes by Ukrainian soldiers are far rarer, but Ukrainian courts must also prosecute these. Fair trials for all combatants are essential, lest, as Aquinas cautions, judgments seek "to sate … hatred under cover of correction."
3. Reparations
Reparations aim to make survivors whole again. This principle, too, has roots in classical just war thinking. The 16th-century theologian Francisco de Vitoria, for example, argued that reparations within the bounds of "equity and humanity" could help redress losses and restore justice.
The World Bank estimates that direct damage in Ukraine is over US$176 billion; in total, rebuilding will cost three times that. The Council of Europe has recommended using frozen Russian assets to fund reconstruction efforts, as have some American scholars . The illegality of Russia's invasion means that such countermeasures are likely permissible under international law.
Apologies can also serve as reparations, but Russia is unlikely to proffer any – partly because domestic political pressures mean Putin cannot afford to look like he has lost.
Commemorative events and memorials also validate victims' suffering. The international community can support Ukrainians in their efforts to meaningfully memorialize the war.
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4. Deterrence
Peace lasts when the parties trust that the violence won't reoccur.
However, Russia has repeatedly broken its treaties with Ukraine. That includes the first agreements meant to bring the conflict to an end, back in 2014.
That summer, Russian-backed separatists downed a Malaysian Airways flight, spurring the international community to seek a quick resolution. The hastily drafted Minsk agreements, signed in 2014 and 2015, established a ceasefire monitoring mission and required the removal of foreign military units. They also demanded Ukrainian constitutional reforms – ostensibly to secure more autonomy for the country's largely Russian-speaking east.
The Minsk agreements temporarily froze the conflict, but relative quiet didn't mean peace. Ceasefire violations were perpetual. Russian-supported militias were not disbanded, and Russia continued to send mercenaries and military forces to the Donbas. Human rights violations proliferated in Russian-occupied areas. And in February 2022, Russia launched its full-scale invasion.
Given this history, a durable peace would require that Russia accept constraints on its power. The various peace proposals put forth since 2022, however, have demanded security concessions only from Kyiv, requiring Ukraine to abandon hopes for NATO membership and restricting the size of its military.
Russia is unlikely to agree to caps on its military. Deterrence, then, could take the form of credible commitments from other countries to enforce whatever peace agreement emerges.
Ukraine's vulnerability to future Russian aggression means it will need binding promises from its partners. Russia will not sign a treaty that permits Ukraine to join NATO, which Moscow claims would be a threat. Other possible safeguards for Ukrainian sovereignty include a proposed international peacekeeping force or an alternative set of security alliances.
Lasting peace
Ultimately, a durable peace requires considering both sides' legitimate security and justice claims if, as Vitoria wrote in 1539, "they are prepared to negotiate genuinely and fairly."
Therein lies the catch. Transnational justice can be hijacked, with aggressors trying to portray themselves as victims. Separating fact from fiction, and genuine concerns from manufactured pretext, is essential at the negotiating table.
A quick end to the war is tempting, but a hasty peace is a fragile one. A durable peace, rather than yet another ceasefire, requires attention to justice – even if that takes more time to achieve.
