In the 1789 Declaration of the Rights of Man and of the Citizen, French revolutionaries proclaimed the freedom of speech, religion, and opinion. Censorship was abolished, and France appeared to be on a path towards tolerance, pluralism, and civil liberties. A mere four years later, the country descended into a period of political terror, as thousands were arrested, tried, and executed for crimes of expression and opinion.

In Policing Public Opinion in the French Revolution, Charles Walton traces the origins of this reversal back to the Old Regime. He shows that while...