Act of changing or suppressing speech or writing that is considered subversive of the common good.
In the past, most governments believed it their duty to regulate the morals of their people; only with the rise in the status of the individual and individual rights did censorship come to seem objectionable. Censorship may be preemptive (preventing the publication or broadcast of undesirable information) or punitive (punishing those who publish or broadcast offending material). In Europe, both the Roman Catholic and Protestant churches practiced censorship, as did the absolute monarchies of the 17th and 18th centuries. Authoritarian governments such as those in China, Cuba, Saudi Arabia, and the former Soviet Union have employed pervasive censorship, which is generally opposed by underground movements engaged in the circulation of samizdat literature. In the U.S. in the 20th century, censorship focused largely on works of fiction deemed guilty of obscenity (e.g., Ulysses and D.H. Lawrence 's Lady Chatterley's Lover ), though periodic acts of political censorship also occurred (e.g., the effort to purge school textbooks of possible left-wing content in the 1950s). In the late 20th century, some called for censorship of so-called hate speech, language deemed threatening (or sometimes merely offensive) to various subsections of the population. Censorship in the U.S. is usually opposed by the American Civil Liberties Union . In Germany after World War II it became a crime to deny the {{link=Holocaust">Holocaust or to publish pro-Nazi publications. See also Pentagon Papers .