Over the past two decades, U.S. and Chinese technological trajectories have been closely linked. Internet protocols, hardware design and manufacturing, software development and deployment, and services and standards have to varying degrees been crossborder phenomena, with China and the United States two of the world’s most consequential and integrated countries. The last few years, however, have seen a rise in mutual suspicion and moves—both direct and indirect—to unwind this extraordinary level of technological interdependence. The overall effect is an increasing degree of separation between the two ecosystems, a process widely known as decoupling...