IN JANUARY 2023, U.S. federal agents raided the home of a Tucson maintenance worker who had a side hustle hauling packages across the border to Mexico.

They estimate that over the previous two years, the gray-bearded courier had ferried about 7,000 kilos of fentanyl-making chemicals to an operative of the Sinaloa Cartel. That’s 15,432 pounds, sufficient to produce 5.3 billion pills – enough to kill every living soul in the United States several times over. The chemicals had traveled by air from China to Los Angeles, were flown or ground-shipped to Tucson, then driven the last miles to Mexico by the freelance delivery driver.

Even more astonishing is what fed this circuitous route: a few paragraphs buried in a 2016 U.S. trade law supported by major parcel carriers and e-commerce platforms that made it easier for imported goods, including those fentanyl ingredients, to enter the United States.