The technological and economic differences between China and the United States wouldn’t matter much if all it took to gain superpower status were the ability to use force locally. But what makes the United States a superpower is its ability to operate globally, and the bar for that capability is high. It means having what the political scientist Barry Posen has called “command of the commons”—that is, control over the air, space, and the open sea, along with the necessary infrastructure for managing these domains. When one measures the 14 categories of systems that create this capability (everything from nuclear attack submarines to satellites to transport aircraft), what emerges is an overwhelming U.S. advantage in each area, the result of decades of advances on multiple fronts. It would take a very long time for China to approach U.S. power on any of these fronts, let alone all of them.