In “The Three-Body Problem” trilogy by Chinese science-fiction author Liu Cixin that was recently adapted into a Netflix series, Earth faces an alien invasion four centuries in the future. To plan and carry out planetary defense, humankind turns to the United Nations. Under a secretary-general who seems to command the authority of a global premier, the U.N. quickly forms a council with the resources and mandate to act on behalf of humanity.

Such sci-fi depictions of the U.N. as a unified, effective world government able to manage planetary crises are as appealing as they are fanciful. Today’s polycrisis of escalating wars, cascading environmental catastrophes and social dislocations calls out for greater international leadership. Yet the U.N. often appears powerless. Security Council resolutions do little to deter Russia’s aggression against Ukraine or Israel’s indiscriminate assault on Gaza. The Sustainable Development Goals are far from being reached. And despite decades of international climate change meetings, carbon emissions continue to rise each year.

Still, the U.N. did seem poised to take a leading role in one emerging global challenge: governing artificial intelligence, which some see as an existential threat not unlike an alien invasion. Few dispute that international cooperation is needed to mitigate the potential risks of AI. Corporate and government leaders alike have called for the creation of various international AI bodies, whether modeled after the Intergovernmental Panel on Climate Change, the International Civil Aviation Organization or the International Atomic Energy Agency. Last year, Secretary-General Antonio Guterres convened an expert advisory panel to propose the features of a possible U.N. AI agency. That ambition received a boost in March, when the U.N. General Assembly unanimously passed a U.S.-led resolution in which all 193 member-states committed to promote safe, secure and trustworthy AI—a rare expression of international consensus.