640px-Oliver Wendell Holmes Jr circa 1930-edit

Justice Oliver Wendell Holmes

Schenck v. United States,1 Justice Oliver Wendell Holmes wrote the now famous:

The most stringent protection of free speech would not protect a man in falsely shouting fire in a theatre and causing a panic. [...] 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.2

Brandenburg v. Ohio3 spelled out the modern test for when government can regulate speech that is otherwise protected that advocates for unlawful activity:

  1. If the speech is directed at inciting or producing imminent unlawful activity; and
  2. If the speech is likely to produce such unlawful activity.

1 249 U.S. 47 (1919).
2 Id. at 49.
3 395 U.S. 444 (1969).