How China’s Cell Phone Spies Track Covid Protesters

US firms helped build Beijing's ubiquitous surveillance systems

China’s anti-lockdown protests last month were the worst blow yet to the prestige of Xi Jinping. One moment, the Chinese Communist Party’s leader was riding high after securing a third term at the top of the party-state. The next, he was challenged by demonstrators in the streets to “step down,” a sentiment that protestors also chanted against the party…