Russia must lose the war outright.

A Russian defeat in Ukraine would strengthen the nonproliferation treaty. Ukrainian success on the battlefield has been achieved with conventional weapons aimed at military targets—not with nuclear weapons causing mass civilian casualties. If the nation possessing the most nuclear weapons in the world is unable to gain victory, the importance of having nuclear weapons will be greatly diminished. And the need to abolish nuclear weapons will be even more obvious. Theories of nuclear deterrence are based on the behavior of rational actors; they offer little protection against leaders who are delusional, suicidal, or religious fanatics. The threat of nuclear annihilation will never vanish until the day when nuclear weapons are stigmatized and abolished.

You don’t have to look far from Russia to find a clear-eyed view of Putin’s intentions. While isolationists and academic socialists in the United States blame the invasion of Ukraine on America’s hegemonic desire for NATO expansion, the social-democratic government of Finland holds a different view. The Finns have a unique, firsthand perspective on Russian imperialism and colonialism. Finland was ruled by Sweden until 1809, when it was conquered by Russia and became part of the Russian empire. Efforts to “Russify” the Finns proved unsuccessful, a strong national identity emerged, and Finland gained independence in 1917. “The Great Patriotic War,” as World War II is called in Russia, began not with the Soviet Union heroically leading the fight against Nazi Germany but with the Kremlin supplying oil to Hitler’s war machine and the Red Army invading Poland and then Finland. Despite being vastly outnumbered and outgunned, the Finns imposed heavy casualties on the Soviets, gained international support, and managed to end the conflict retaining almost all of their territory. Finland remained neutral during the Cold War and built up a formidable army purely for self-defense. It can now mobilize about 1 million soldiers and reservists—nearly one-fifth of the population.

Sauli Niinisto, the president of Finland, maintained a cordial relationship with Putin until recently, speaking with him more than 40 times in person or over the phone during the past decade. And Finland long served as a discreet intermediary between the White House and the Kremlin. But the invasion of Ukraine shattered any illusion that Russia could be a trustworthy neighbor. Finland’s break from its tradition of neutrality and its application to join NATO mark a radical turn in the nation’s history. And it has more military significance than Ukraine’s potential membership in NATO. Russia and Finland share a border that’s almost 800 miles long. St. Petersburg is closer to the Finnish border than it is to Moscow. Finland’s membership in NATO will help the alliance dominate the Baltic Sea, threaten Russia’s crucial nuclear bases on the Kola Peninsula, and transform the strategic balance in the Arctic. And yet Russia hasn’t described Finland’s desire to join NATO as an existential threat that merits nuclear annihilation. The Finns know the Russians too well to be intimidated by that bluff.

A proper conclusion of the war in Ukraine will require many complex issues to be resolved: war crimes, reparations, prisoner-of-war exchanges, the return of children kidnapped by Russia. The Ukrainian government, not the United States or NATO, will have to decide how to proceed. But the basis of a just settlement is simple. When a reporter asked Sanna Marin, the prime minister of Finland, whether Russia should be given an “off-ramp” to avoid its humiliation and prevent nuclear war, she didn’t fully understand the question at first. The term “off-ramp” seemed unfamiliar to Marin. A way out of the conflict, the reporter explained. “A way out of the conflict?” Marin asked. “The way out of the conflict is for Russia to leave Ukraine. That’s the way out of the conflict. Thank you.” Then she turned, smiled, and walked away.