freedom of speech, right, as stated in the 1st and 14th Amendments to the Constitution of the United States, to express information, ideas, and opinions free of government restrictions based on content. A modern legal test of the legitimacy of proposed restrictions on freedom of speech was stated in the opinion by Oliver Wendell Holmes, Jr. in Schenk v. U.S. (1919): a restriction is legitimate only if the speech in question poses a “clear and present danger”—i.e., a risk or threat to safety or to other public interests that is serious and imminent. Many cases involving freedom of speech and of the press also have concerned defamation, obscenity, and prior restraint (see Pentagon Papers). See also censorship.