The 2020 census was marketed as an “actual enumeration,” a neutral count of people for apportionment and funding. It was not. The same official who helped block a basic citizenship question in 2018, John M. Abowd, then the Census Bureau’s Chief Scientist, pushed through a new, opaque methodology in 2020 called differential privacy. The new system deliberately injected mathematical noise into every block count in America, turning the census from a headcount into a model with knobs. The knob that mattered most was a single parameter, epsilon, a secrecy shroud known only to a small inner circle. Abowd argued that...