CLEAR AND PRESENT DANGER is a Supreme Court doctrine concerning the limits of Free Speech
Before the 20th century, most free speech issues involved prior restraint. Starting in the early 1900s, the Supreme Court began to consider cases in which persons were punished 'after' speaking or publishing. The primary legal test used in the United States to determine if speech could be criminalized was the bad tendency test.[1] Rooted in English common law, the test permitted speech to be outlawed if it had a tendency to harm public welfare.[1] One of the earliest cases in which the Supreme Court addressed punishment after material was published was 1907's Patterson v. Colorado in which the Court used the bad tendency test to uphold contempt charges against a newspaper publisher who accused Colorado judges of acting on behalf of local utility companies.[1][2]
Antiwar protests during World War I gave rise to several important free speech cases related to sedition and inciting violence. In the 1919 case Schenck v. United States, the Supreme Court held that an antiwar activist did not have a First Amendment right to advocate draft resistance.[3][4] In his majority opinion, Justice Oliver Wendell Holmes, Jr. introduced the clear and present danger test, which would become an important concept in First Amendment law; but the Schenck decision did not formally adopt the test.[3] Holmes later wrote that he intended the clear and present danger test to refine, not replace, the bad tendency test.[5][6] Although sometimes mentioned in subsequent rulings, the clear and present danger test was never endorsed by the Supreme Court as a test to be used by lower courts when evaluating the constitutionality of legislation that regulated speech.[7][8]
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 the United States Congress has a right to prevent. It is a question of proximity and degree. When a nation is at war, many things that might be said in time of peace are such a hindrance to its effort that their utterance will not be endured so long as men fight, and that no Court could regard them as protected by any constitutional right.
The Court continued to use the bad tendency test during the early 20th century in cases such as 1919's Abrams v. United States, which upheld the conviction of antiwar activists who passed out leaflets encouraging workers to impede the war effort.[9] In Abrams, Holmes and Justice Brandeis dissented and encouraged the use of the clear and present test, which provided more protection for speech.[10] In 1925's Gitlow v. New York, the Court extended the First Amendment to the states, and upheld the conviction of Gitlow for publishing the "Left Wing Manifesto".[11] Gitlow was decided based on the bad tendency test, but the majority decision acknowledged the validity of the clear and present danger test, yet concluded that its use was limited to Schenck-like situations where the speech was not specifically outlawed by the legislature.[5][12]
Brandeis and Holmes again promoted the clear and present danger test, this time in a concurring opinion in 1927's Whitney v. California decision.[5][13] The majority did not adopt or use the clear and present danger test, but the concurring opinion encouraged the Court to support greater protections for speech, and it suggested that "imminent danger" – a more restrictive wording than "present danger" – should be required before speech can be outlawed.[14] After Whitney, the bad tendency test continued to be used by the Court in cases such 1931's Stromberg v. California, which held that a 1919 California statute banning red flags was unconstitutional.[15]
The clear and present danger test was invoked by the majority in the 1940 Thornhill v. Alabama decision in which a state antipicketing law was invalidated.[7][16] Although the Court referred to the clear and present danger test in a few decisions following Thornhill,[17] the bad tendency test was not explicitly overruled,[7] and the clear and present danger test was not applied in several subsequent free speech cases involving incitement to violence.[18]
https://en.wikipedia.org/wiki/Clear_and_present_danger