In 1919, in Schenck v. United States and Abrams v. United States, the U.S. Supreme Court made its initial foray into establishing the meaning of the First Amendment’s free speech clause. Those cases involved prosecutions that were reactions to the Left’s opposition to World War I and to the Red Scare following the Russian Revolution of 1917. In both cases, the Court upheld the defendants’ convictions of conspiracy to urge others to obstruct the war effort. In Schenck, Holmes wrote the opinion of the Court and announced the so-called “clear and present danger” test. (“The question in every case is whether the words used are used in such circumstances and are of such a nature as to create a clear and present danger that they will bring about the substantive evils that Congress has a right to prevent.”) In Abrams, Holmes dissented, arguing that the test in Schenck was not satisfied.
Larry Alexander, Inciting, Requesting, Provoking, or Persuading Others to Commit Crimes: The Legacy of Schenck and Abrams in Free Speech Jurisprudence, 72 SMU L. Rev. 389 (2019).