From "The Reader's Companion to American History"
The modern American conception of freedom of speech derives from the principles of freedom of the press (mainly in the context of political criticism) and freedom of religion as they developed in England, starting in the seventeenth century. The arguments of John Milton and others on the importance of an unlicensed press, and of John Locke and others on religious toleration, were the precursors to the idea of freedom of speech, although also relevant is the much narrower concept of “freedom of speech” as an immunity for prosecution for anything said in the course of parliamentary debate.
By 1791, when the First Amendment was ratified, the idea of “freedom of speech” was sufficiently entrenched that it became the primary language of the amendment, with “freedom of the press” being added to ensure that written and printed as well as oral communication was protected: “Congress shall make no law ... abridging the freedom of speech, or of the press.” Still, the focus both in law and in political discussion at the time was on printed political argument, whether in newspapers or the kinds of tracts distributed by men like Thomas Paine.
The period from 1791 to the early twentieth century saw almost complete judicial noninvolvement in free speech and free press questions, and public discussion was devoted largely to free press rather than free speech ideas. But when the Supreme Court actively began in 1919 to concern itself with judicial enforcement of the First Amendment, it was in the context not of newspapers or magazines or books but of speakers, or occasionally pamphleteers, who were protesting American involvement in the First World War or promoting anarchist, socialist, or syndicalist causes. Although the convictions were upheld and the speakers imprisoned in cases involving the now-forgotten figures Charles T. Schenck, Jacob Abrams, and Jacob Frohwerk, as well as prominent ones such as Eugene V. Debs, the Supreme Court’s language in those cases has had an enduring effect. In upholding the convictions of Schenck, Frohwerk, and Debs, Justice Oliver Wendell Holmes, Jr., enunciated the principle of the
“clear and present danger,” according to which, to justify regulation, the harms resulting from speech had to be greater in likelihood and immediacy than harms of other varieties. And in dissenting from the conviction of Abrams, Holmes developed the notion of the “marketplace of ideas,” which has dominated public understanding of the importance of freedom of speech.
The development of freedom of speech for the next forty years was also dominated by Supreme Court protection of largely oral and frequently socially marginal communicators, of whom the most important were the Jehovah’s Witnesses. In case after case in the 1930s, 1940s, and 1950s, they challenged restrictions on their proselytizing activities and won in the Supreme Court and in the lower courts with sufficient frequency that their victories established in legal doctrine and public consciousness the principle that even annoying, intrusive, and offensive speech is to be protected by the courts and tolerated by the public as incidental to an open society.
Contemporary understandings of freedom of speech, however, owe even more to developments in the 1960s, during which first civil rights protesters and then objectors to the Vietnam War found the courts upholding their activities against governmental efforts to restrict them. Increased public acceptance of such activities followed. In this respect, the modern protection of freedom of speech is partly fortuitous, for the protection of civil rights demonstrators, paraders, and picketers in the 1960s was largely an adjunct to judicial protection of the civil rights movement generally. Nevertheless, the First Amendment principles developed to further the civil rights movement remained in place to be used for other speakers promoting other causes.