As Covid-19 spread from China to Europe and then the United States, pandemic-stricken countries found themselves in a mad scramble for medical supplies such as masks, ventilators, and protective garments. More often than not, it was to China that they had to turn. By the time the crisis erupted, China had become the world’s largest supplier of key products, accounting for half of all European and US imports of personal protective equipment. “China has laid the groundwork to dominate the market for protective and medical supplies for years to come,” according to recent reporting by The New York Times.

When...