President Joe Biden came away from his summit with China’s President Xi Jinping on Nov. 15 committed to prosecuting what he called “simple, straightforward competition” with China. Yet Beijing is already beating the United States and its allies in one crucial domain: data. Data is the oil of the 21st century, the indispensable resource that will fuel artificial-intelligence algorithms, economic strength and national power. The wellspring of this data is all of us: our health records and genetic sequences, our online habits, the supply chain flows of our businesses, the terabytes of imagery guzzled by phones, drones and autonomous cars....