Russia is increasingly aware of its own weakness. Far from expanding Putin’s imperial ambitions, the war in Ukraine has narrowed them. On Monday, the Kremlin dropped its demand for regime change in Kyiv, asking instead for recognition of Ukraine’s breakaway provinces as independent republics and a constitutional amendment that would forbid Ukraine from joining NATO or the E.U. This is a large comedown from the expansive war aims Putin articulated at the conflict’s outset and is broadly similar to the concessions Russia sought before it brought military force to bear on Kyiv.

In light of these developments, it is not credible to suggest that the fall of Ukraine would presage the fall of Europe. Nor is there much basis for the claim that failure to confront Russia in Ukraine will inspire aggression from other nuclear-armed states. The West has not risked nuclear war to defend against wars of conquest. But it has sacrificed its own economic best interests toward that aim and established a formidable deterrent against offensive wars in the process. To the extent that Putin’s Ukraine adventure has influenced Xi Jinping’s plans for Taiwan, it has surely made the prospect of war less attractive to Beijing.

All of which is to say: There is no basis for believing that NATO’s abstention from direct involvement in Ukraine will imperil the rest of Europe or the international order writ large. By contrast, any attempt to establish a no-fly zone would guarantee a war between Europe’s great powers. Ironically, the apparent weakness of Russia’s conventional forces only makes the Kremlin a more dangerous player in any great-power war: If Russia cannot compete with NATO on the strength of its conventional military resources, its incentive to deploy nuclear weapons will be all the greater. To advance the best interests of the Ukrainian people without jeopardizing those of humanity writ large, the West must push for a negotiated settlement, not shoot Russian planes from the sky.