Bangladesh, Sept. 24 -- The United Nations was created in the aftermath of the Second World War with an ambitious purpose: to prevent another global catastrophe, provide a forum for diplomacy and help nations resolve disputes without resorting to war. Eight decades later, however, the organization is confronting perhaps its most profound crisis of relevance.

Wars are spreading or becoming more entrenched, geopolitical rivalries are intensifying, climate change is accelerating, artificial intelligence is creating new risks, and the international system is increasingly divided between competing blocs. At the same time, the principles that once gave multilateralism its authority - cooperation, compromise, international law and collective re...