Eric Posner, a professor of law at the University of Chicago, hasn’t actually censored anyone, so he doesn’t make the list. But he certainly provides a great deal of intellectual ammunition for people working to restrict free expression rights—including and especially university administrators, as well as the police. Whether he is arguing that 18-year-olds are better off with fewer rights, or that vast infringements on internet freedom are necessary in order to protect the U.S. from ISIS, Posner is a reliable ally of would-be muzzlers everywhere.