I understand those who fear that, confronted with an impending loss, Putin will seek to use chemical or nuclear weapons; I worried the same at the start of the war. But the retreats from Kyiv and Kharkiv indicate that Putin is not irrational after all. He understands perfectly well that NATO is a defensive alliance, because he has accepted the Swedish and Finnish applications without quibbling. His generals make calculations and weigh costs. They were perfectly capable of understanding that the price of Russia’s early advances was too high. The price of using tactical nuclear weapons would be far higher: They would achieve no military impact but would destroy all of Russia’s remaining relationships with India, China, and the rest of the world. There is no indication right now that the nuclear threats so frequently mentioned by Russian propagandists, going back many years, are real.

By contrast, a true defeat could force the reckoning that should have happened in the 1990s, the moment when the Soviet Union broke up but Russia retained all of the trappings and baubles of the Soviet empire—its UN seat, embassies, diplomatic service—at the expense of the other ex-Soviet republics. The year 1991 was the moment when Russians should have realized the folly of Moscow’s imperial overreach, when they should have figured out why so many of their neighbors hate and fear them. But the Russian public learned no such lesson. Within a decade, Putin, brimming with grievances, had convinced many of them that the West and the rest of the world owed them something, and that further conquests were justified.

Military loss could create a real opening for national self-examination or for a major change, as it so often has done in Russia’s past. Only failure can persuade the Russians themselves to question the sense and purpose of a colonial ideology that has repeatedly impoverished and ruined their own economy and society, as well as those of their neighbors, for decades. Yet another frozen conflict, yet another temporary holding pattern, yet another face-saving compromise will not end the pattern of Russian aggression or bring permanent peace.