At the United Nations this week, the leaders building the world's most powerful artificial intelligence systems made an unusual plea: that the technology they profit from must be governed by something larger than any single company or nation. The American government, however, answered that global coordination is a constraint the United States cannot afford in its contest with China. In this collision between those who build the future and those who command it, the question of who will govern artificial intelligence — and by what values — remains dangerously open.