Public debate is not like a trial. It does not have rules of evidence, opportunities to cross-examine witnesses, or methods to scrutinize documents. In the context of Holmes’s marketplace of ideas, individual citizens often do not have the resources to make reasonable judgments about the truth and falsity of competing factual claims. If one side says X and the other says not-X, how is the citizen to know who is lying?

This is where the free press enters the picture. One function of a free press in a self-governing society is to serve the public’s interest in learning the truth. Unlike individual citizens, the media have the resources to check facts and to separate truth from falsity in a professional and objective manner. The media can be a relatively neutral and detached referee when one side accuses the other of lying, and the capacity of the press to help resolve such factual disputes can serve as a powerful restraint on political lies.