So, with that general background in mind, let us have a look at early First Amendment cases before the Supreme Court.
The first case widely quoted was Schenck v. US. The case was actually decided in 1919, after WWI was over, but while the post-war Red Scare was at its height. The Bolsheviks had taken over Russia and were engaged in civil war against a wide range of opponents. The Bolsheviks had only recently changed their name to Communist and founded the Comintern, an international organization of Communist parties, all taking orders from Moscow, and trying to stir up revolution in prostrate belligerents of the war. Left-wing revolution and attempted revolution and right wing repression were breaking out all across Europe. The United States was not spared as radical Socialists declared general strikes, government and veterans cracked down, and the worst race riots since Reconstruction gripped the land. A short but severe post-war depression did not help. It was in this atmosphere that the Supreme Court received the appeal of the prosecution of Charles Schenck, a Socialist for circulating anti-draft pamphlets to young men subject to the draft, urging them to resist. He had not engaged in any sabotage or terrorism. Convicted, Schenck appealed on the grounds that the pamphlets were protected by the First Amendment. The Supreme Court unanimously upheld the conviction in an opinion written by Oliver Wendell Holmes. Holmes conceded that the First Amendment might do more that just forbid prior restraints (this issue had never been decided at the time). He also conceded that "in ordinary times" saying all that was in the circular would have been protected. But he argued that war as an extraordinary situation, and that if obstructing the draft could be a crime, so could conspiracy to obstruct the draft, as by circulating pamphlets. The opinion contains two famous quotes. "The most stringent protection of free speech would not protect a man in falsely shouting fire in a theatre and causing a panic." This, of course, is usually paraphrased as, "Freedom of speech does not include the right to yell fire in a crowed theater." Holmes was arguing that circulating such pamphlets in wartime was tantamount to yelling fire in a crowded theater. He also argued that the First Amendment did not protect words that "create a clear and present danger that they will bring about the substantive evils that Congress has a right to prevent." "Clear and present danger" has become a watchword for when free speech may be restricted.
Most accounts I have read of the First Amendment cite Holmes' authorship of Schenck and leave it at that. They go on to describe how Louis Brandeis began dissenting, how he won Holmes over, and how the two of them ultimately changed the mind of the entire Supreme Court. But Wikipedia gives a fascinating and little-known sidelight. An earlier case reached the Supreme Court in which the defendant was prosecuted for signing an anti-war petition. While the majority favored upholding the conviction, Holmes wrote a dissent powerful enough that the Court backed down and dropped the case altogether. So apparently Holmes had some unease with such prosecutions from the start.
The Supreme Court ruled the same way, again in 1919, again unanimously and again in an opinion by Holmes in Frohwerk v. US. This time, the defendant was prosecuted for publishing an anti-war newspaper. The paper was not specifically sent out to potential draftees, but was quite strong in its denunciations of the war, sometimes to the point of appearing to favor Germany over England. Holmes acknowledged that, "We do not lose our right to condemn either measures or men because the country is at war," but argued that speech advocating a crime was not protected. And, as in Schenck, the Court held that an anti-draft publication was sufficient grounds for conviction for conspiring to thwart the draft.
Holmes made it three for three in the unanimous Supreme Court cases he wrote in 1919 when he wrote Debs v. US, this time upholding the conviction of Socialist leader Eugene Victor Debs for an anti-war speech. This time Holmes felt the need to emphasize that criticizing the war was not, in and of itself, a crime, so long as the criticism did not interfere with the draft. But Debs praised people imprisoned for interfering with the draft, and that was grounds enough for the Supreme Court to uphold his conviction.
But he changed his mind, still in 1919, in the case of Abrams v. US, in which the Supreme Court upheld yet another conviction under the Espionage and Sedition Acts but Holmes, joined by Louis Brandeis, dissented. In that case, four Russian Jewish anarchists and one socialist distributed anti-war pamphlets directed primarily at US intervention in Russia's civil war, and including some that openly called for revolution or at least strikes in the munitions industry. They were convicted under the Espionage and Sedition Acts, and appealed on the grounds that their publications were protected by the First Amendment. By a vote of 7-2, the Supreme Court upheld their conviction, but this time Holmes dissented. This case was a bit delicate because, despite the inflammatory language of the leaflets, they were not actually directed at our official, declared war against Germany, but only against our unofficial, undeclared intervention in Russia's civil war. Technically speaking, the Sedition Acts were only aimed at speech the disrupted the war against Germany. In fact, the defendants argued just that. The majority, however, said that their call for a general strike would disrupt the war effort against Germany, so the speech was illegal. As for the First Amendment, the majority simply cited Schenck and Frohwerk to show otherwise.
Holmes, joined by Brandeis, dissented. He argued first that calling for a general strike did not violate the Acts unless it was done with the specific intent to disrupt the war with Germany. More importantly, he argued that the First Amendment allowed speech to be criminalized only if it posed a "clear and imminent danger" of illegal conduct. This standard applied either in war or in peace, although it might be more stringently applied during war. He also argued that the intent to bring about illegal conduct with one's speech was a necessary condition to it being subject to prosecution. Here, the intent was to disrupt the intervention in Russia, not the war with Germany, so there was no criminal intent. Holmes cited, of all cases, Schenck, Frohwerk, and Debs to support his dissent, even those these cases upheld prosecution of less inflammatory speech. And finally, for the first time in the history of the Supreme Court, Holmes agreed with the court of public opinion and expressed the view that the Alien and Sedition Acts of 1798 were unconstitutional.
I intend to follow soon with more cases on the growing acceptance of free speech rights by radical groups.