The First Amendment means to me, however, that the only constitutional way our Government can preserve itself is to leave its people the fullest possible freedom to praise, criticize or discuss, as they see fit, all governmental policies and to suggest, if they desire, that even its most fundamental postulates are bad and should be changed.
Hugo Black (1886-1971) American politician and jurist, US Supreme Court Justice (1937-71)
Barenblatt v. United States, 360 U.S. 109, 145-46 (1959) [dissent]
(Source)