In United States law, the bad tendency principle was a test[1] that permitted restriction of freedom of speech by government if it is believed that a form of speech has a sole tendency to incite or cause illegal activity.
The principle, formulated in Patterson v. Colorado (1907), was seemingly overturned with the "clear and present danger" principle used in the landmark case Schenck v. United States (1919), as stated by Justice Oliver Wendell Holmes Jr.
Yet eight months later, at the start of the next term in Abrams v. United States (1919), the Court again used the bad tendency test to uphold the conviction of a Russian immigrant who published and distributed leaflets calling for a general strike and otherwise advocated revolutionary, anarchist, and socialist views.
The court ruled unanimously that although she had not committed any crimes, her relationship with the Communists represented a "bad tendency" and thus was unprotected.
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