The world knows an unjust war when it sees one. That is why Russian President Vladimir Putin’s unprovoked invasion of Ukraine has attracted such widespread condemnation. But negotiating a peace settlement—the key to ending most wars—will require attention not only to justice, but also to stability and balance between competing national interests and ambitions. The question, then, is: What would a stable peace in Ukraine look like?

In theory, nothing short of true justice in Ukraine should suffice. That means ensuring Russia’s unconditional defeat, the restitution of Ukraine’s full territorial integrity and possibly even reparations from Russia to help fund Ukraine’s reconstruction.

For many observers, this outcome seems entirely likely. Some, such as Russian opposition politician Vladimir Milov, argue ^[1] that Putin’s days in power are numbered. Others believe that Russia will suffer a decisive defeat on the battlefield. British historian Antony Beevor, for one, anticipates ^[2] a military collapse and humiliating withdrawal. Author Yuval Noah Harari has assured ^[3] us that Putin lost the war the day he started it.

But the era of glorious wars, overwhelming victories, and clear-cut defeats is over. Yes, Putin’s murderous army is an inefficient, clumsy machine that has not moved beyond the archaic tactics of World War II. Yet the combination of barbarism and sheer numbers—‘quantity has a quality of its own’, said ^[4] Stalin—has enabled Putin to achieve significant territorial gains in eastern Ukraine and along the Black Sea coast.

Of course, the West is providing vast—and growing—military aid to Ukraine, which could tip the scales to some extent, especially given Russia’s international isolation. But this remains an asymmetric war, not least because it is happening on Ukrainian soil. As a result, Ukraine’s economy cannot function, and Russian soldiers can target civilians—something that, as multiple reports and videos ^[5] show, they have not hesitated to do.

Mutually damaging deadlocks have often spurred progress towards peace settlements. But, in the current war, a military deadlock would hurt Ukraine far more than it would hurt Russia, even if Putin refrains from using chemical or tactical nuclear weapons. If he does cross that line, the costs to Ukraine would skyrocket.

This is a real risk. Though the West is attempting to calibrate its military aid to Ukraine to avoid provoking a Russian escalation, the pressure on Putin is intensifying. Indeed, judging by his Victory Day speech ^[6], he is well aware of both his military’s limits and the fragility of Russian public opinion.

Many feared Putin would use the commemoration of Russia’s victory over Nazi Germany to issue a formal declaration of war on Ukraine, which would have allowed him to send hundreds of thousands of young conscripts to the battlefield. But that day has come and gone, and the war remains a ‘special military operation’ in Russia. Putin, it seems, did not want to risk stirring popular opposition.

But this might not be a reason for celebration. Lest we forget, Russia possesses the world’s largest nuclear arsenal ^[7], and Putin has both the unconstrained authority to use it and an inability to accept defeat. Autocrats who lose wars lose power—and, sometimes, their heads. If Putin feels backed into a corner, he may well view deployment of tactical nuclear weapons as the minimum requirement to save face.

This points to the dangers of a weakened Russia. But even a resounding Russian defeat is an ominous scenario. Yes, under such circumstances—and only such circumstances—Putin might be toppled in some kind of coup led by elements of Russia’s security apparatus. But the chances that this would produce a liberal democratic Russia that abandons Putin’s grand strategic designs are slim. More likely, Russia would be a rogue nuclear superpower ruled by military coup-makers with revanchist impulses. Germany after World War I comes to mind.

As they seek to engineer Russia’s defeat in Ukraine, the United States and its NATO allies must not lose sight of what happens the day after. A vast, nuclear-armed and humiliated power cannot simply be isolated or ignored. Even as they help Ukraine resist Putin’s aggression, they must attempt to integrate Russia into Europe’s broader security architecture, reshaping that architecture in response to Russia’s concerns. Otherwise, Putin cannot make sufficient concessions without jeopardising his political, if not physical, survival.

Beyond ending its bid to join NATO and maintaining an Austria-like neutrality—concessions to which Ukrainian President Volodymyr Zelensky has all but agreed ^[8]—a settlement on the ethnic Russian regions of Donetsk and Luhansk, whose ‘independence ^[9]’ Putin recognised days before the invasion, will be needed. A form of self-government, along the lines laid out ^[10] in the 2015 Minsk II agreement, might be the answer.

Putin is highly unlikely to agree to reverse Crimea’s annexation, even in exchange for the clarification of the status of Russia’s Black Sea Fleet at Sevastopol. But he may be convinced to shelve his dream of a territorially contiguous Russian sphere of influence stretching from Moscow all the way to the Black Sea. He should also agree to respect the territorial integrity of both Moldova and Georgia.

The responsibility for convincing Putin to make these concessions, in exchange for appropriate strategic arrangements, falls primarily on the US. After all, in Putin’s view, Russia is currently fighting the US and NATO—not just Ukraine. US President Joe Biden recognises ^[11] the dangers of a cornered Putin, so he should offer a face-saving exit strategy. The economic impact of sanctions, the progressive weakening of Russia’s military, the spectre of a guerrilla war of attrition against his demoralised army, and a lack of international support for Russia should motivate Putin to accept a reasonable offer.

That offer will not deliver the justice Ukrainians deserve. But nor will it be a triumph for Russia. Instead, it will be a mutually unsatisfactory, but ultimately tolerable, arrangement—disappointing to all, but better than the alternatives.