The tendency for people to band together when state power is weak is so inevitable it can even seem innate. “The latent causes of faction,” wrote founding father James Madison, are “sown in the nature of man.” Without law, people use violence collectively to settle scores and right wrongs, and commonly refer to violence as their own law. Wherever law is absent or undeveloped—wherever it is shabby, ineffective, or disputed—some form of self-policing or communal justice usually emerges.

