Clear and present danger

Overview
Clear and present danger was a term used by Justice Oliver Wendell Holmes, Jr. in the unanimous opinion in the case Schenck v. United States, concerning the ability of the government to regulate speech against the draft during World War I:

"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."

Following Schenck v. United States, "clear and present danger" became both a public metaphor for First Amendment speech and a standard test in cases before the U.S. Supreme Court where a U.S. law sought to limit a citizen's First Amendment rights; the law would be deemed constitutional if it could be shown that the language it prohibited posed a "clear and present danger." However, the "clear and present danger" criterion in Schenck was replaced in 1969 by Brandenburg v. Ohio, and the test refined to determining whether the speech would provoke an "imminent lawless action."