Every ten years the United States tries to count every single person in the country. The Constitution requires it, and the result quietly redistributes political power across the entire nation.
The census is the official count of the population. In the United States it is taken every ten years, and it is not optional, it is written directly into the Constitution, in Article I.
The word and the practice are Roman. A magistrate called the censor conducted Rome's count, from the verb censere, to assess. The same office that counted citizens also policed their morals, which is why censor and censorship share the root.
America made a crucial innovation. The first US census, in 1790, was the first in history designed to fully enumerate a population in order to apportion political representation. The count determines how many seats each state gets in the House and how many electoral votes it casts.
Because power follows the count, the census is intensely political. Who is counted, and where, shifts seats, electoral votes, and billions in federal funding between states. Fights over how the count is conducted are, underneath, fights over power.
