Most American historians and legal scholars incorrectly assume that controversies and litigation about free speech began abruptly during World War I. However, there was substantial debate about free speech issues between the Civil War and World War I. Important free speech controversies, often involving the activities of sex reformers and labor unions, preceded the Espionage Act of 1917. Scores of legal cases presented free speech issues to Justices Holmes and Brandeis. A significant organization, the Free Speech League, became a principled defender of free expression two decades before the establishment of the ACLU in 1920. World War I produced a major transformation in American liberalism. Progressives who had viewed constitutional rights as barriers to needed social reforms came to appreciate the value of political dissent during its wartime repression. They subsequently misrepresented the prewar judicial hostility to free speech claims and obscured prior libertarian defenses of free speech based on commitments to individual autonomy.