During the Middle Ages, scribes copied books by hand. Their output was scarce and expensive, elaborately bound as precious objects and chained to library shelves. Unorthodox or heretical works did not get copied. Gutenberg changed all that. Printing made books exponentially cheaper. Printing technology was open to any literate layman with the capital to afford a press and a case of type. The circulation of written matter increased, and the range of what could be circulated expanded. Disruptive consequences followed, starting with the Protestant-Catholic schism known as the Reformation.

It took almost 100 years after the invention of printing for religious and secular powers-that-be to get this radical new information technology under control by a system of licensing printers and pre-publication clearance. The English system of prior restraint did not lapse until after 1689, and the French until the French Revolution. Only the Dutch Republic allowed more or less free printing.

Things happen faster in the 21st century. The internet as a form of exponentially cheaper mass publishing and circulation dates back only to the invention of the web browser in the early 1990s. What we call social media, which is a series of advertiser-supported platforms on which anybody can create and circulate content without paying to maintain their own website, is not yet 20 years old. The demand for censorship is already growing.

During the 20th century, it was said that freedom of the press was only freedom for the man who owned a press. That is no longer true. The power of private publishers and educated editors to decide what was worth printing—for financial, aesthetic or ideological reasons—is gone. As Matt Drudge was the first to figure out, there are no more intermediaries, no more editor's spike or publisher's slush pile. What used to be circulated only in barroom conversation or mimeographed leaflets now has as much chance to find a mass audience willing to believe as the New York Times, the Wall Street Journal, or the cable news networks. The words of the prophets need no longer be written on subway walls and tenement halls; they are on Facebook, Twitter and YouTube.

As the post-Cold War Western order comes under increasing economic, demographic and political stress, its patrons and supporters have grown increasingly concerned that the wrong people have gained the power to publish the wrong things to the wrong audience, and that too many people are paying too much attention. We are now in the early stages of demand by the righteous, great and good that “Something Must Be Done” to bring politically or morally objectionable content on the Internet—”fake news,” “hate speech,” or whatever other term of opprobrium—under some form of intermediation and control.

For authoritarian governments, this poses no problem; China, Russia and Iran have used all available technical means to block and punish the circulation of objectionable content, with considerable success. European governments with firsthand experience of fascism seem to be comfortable controlling online expression that they deem socially dangerous. For the United States, with its robust tradition of unfettered speech, it is a much tougher issue.

To start with, the new media are private monopolies. Unlike printing, network effects mean that there is for practical purposes only one social network, one instant broadcaster, one universal video library, and one general interest search engine. The need of both creators and consumers to go where everyone else is tends to drive second-best alternatives to extinction or life support. The owners have as yet unchecked power to guide access by their search algorithms. Federal law, Communications Decency Act § 230, has encouraged them not to discriminate on the basis of content by exempting websites from civil liability for content posted by third parties.

We are now beginning to see demand that these owners take more responsibility, which means assert more authority over what they allow to be circulated. Much of that demand assumes that the men who own and control these platforms can be trusted with this imprimatur because they share the political and moral principles of conventional upper-middle class progressives. As Sen. Cruz's recent complaints about Facebook's treatment of a pair of pro-Trump rappers reminds us, though, private control of content sits uneasily with monopoly power over the medium of communication. There would be a lot less demand for Facebook and Google to restrict or disfavor content if their owners were thought to have the views of Rebekah Mercer or David Koch. Private regulation cannot be sensibly discussed without addressing the natural monopoly position of online communication networks.

Government control in this country would run up against the limits of the First Amendment. Except in the case of knowingly false statements of fact about particular persons, obscenity, threats, or immanent incitements to violence, the First Amendment does not permit the state to police the content of published speech, or to protect the public mind from being debauched by lies or by appeals to fear and hatred or to revolution. Moreover, it also protects the right to anonymous or pseudonymous political speech, whatever the author's motive for concealment. As Justice Black pointed out in Talley v. California (1960), anonymous speech protects the persecuted and unpopular. As Justice Stevens added in McIntyre v. Ohio Elections Commission (1995), “on occasion, apart from any threat of persecution, an advocate may believe that her ideas will be more persuasive if her readers are unaware of her identity.” As both opinions note, “the Federalist Papers were published under fictitious names.” As long as this remains the law, the government is not going to protect the pure well of American public discourse, such as it is, from pollution by foreign or domestic trolls. For the time being, we are stuck with Jefferson's faith, possibly naïve, that the public can distinguish truth from falsehood if given access to both. Where the crisis of that faith will lead, it is too soon to tell.