A decade ago, few people in Beijing would have predicted that China would challenge the U.S. anytime soon. China’s decades-long economic boom was slowing, and the government’s chokehold on free thought was sending ambitious people abroad. The Chinese establishment has abandoned that view in stages. When Brexit was approved, in 2016, the West seemed to be turning inward. The fight over COVID-19 vaccines provided a signal that the U.S. was splintering; the storming of the Capitol offered another.