Censorship as Optimal Persuasion

A sender designs a signal about the state of the world to persuade a receiver. Under standard assumptions, an optimal signal censors states on one side of a cutoff and reveals all other states. This result holds in continuous and discrete environments with general and monotone partitional signals. The sender optimally censors more information if she is more biased, if she is more certain about the receiver's preferences, and if the receiver is easier to persuade. We apply our results to the problem of media censorship by a government.