Though the UN Security Council remains paralyzed on issues related to Russia’s war on Ukraine, the institution as a whole has so far not descended into the irrelevance of the 1930s League of Nations. Still, the promise of the UN Charter’s language “to save succeeding generations from the scourge of war” did not protect Ukraine from Russia’s invasion—a blatant violation of the UN’s purpose to prevent military aggression. In this talk, Jeffrey Feltman asks if this moment has prompted sufficient international support for the evolution of the UN and the broader postwar multilateral architecture. Drawing on his experience as UN Under Secretary General for Political Affairs, he also discusses the UN and multilateralism against the backdrop of an increasingly polarized environment in which autocratic and populist leaders are threatening to upend the liberal values long ensconced in today’s overarching multinational system.