The national American Civil Liberties Union was formed in January 1920 largely through the efforts of Roger Baldwin, who began his career in St. Louis. 

Baldwin moved to St. Louis from Boston in the fall of 1906 to be the first director of Self Culture Hall, a neighborhood settlement house founded by the Ethical Culture Society.  In addition to this position, Baldwin gave the first course in sociology at Washington University.  Along with his involvement in urban reform; he served as secretary of the St. Louis Civic League, an organization of urban progressives, Baldwin counseled pacifism at the outbreak of the First World War in Europe.  "When I read of the British conscientious objectors in the war", he recalled, "I knew I was one of them."  In 1916 he joined the St. Louis affiliate of the American Union Against Militarism (AUAM) and in the spring of 1917 Baldwin resigned his position with the Civic League and moved to New York in order to donate his services to the AUAM national directing committee.

In May, 1917 Baldwin organized the Bureau for Conscientious Objectors as a sub-agency of the AUAM to advise objectors about legal technicalities and in other ways provide legal or economic assistance.  Due to ideological differences, Baldwin's organization broke away from the AUAM and became the National Civil Liberties Bureau (NCLB) an independent association, in 1917.  In the fall of 1918, just as the war was about to end, Baldwin went to prison for eight months for violating the draft law.  Following his release from prison in late 1919, Baldwin began a reorganization of the NCLB.  Taking a broader scope than before, he sought to serve those directly involved in the labor struggle and those  who stood on general principles for freedom of expression. Baldwin's efforts resulted in the organization of the American Civil Liberties Union in January, 1920.

The St. Louis Civil Liberties Committee (SLCLC) was formed May 7, 1920  when Roger Baldwin visited St. Louis and  oganized a “branch of the American Civil Liberties Union” with a small group of St. Louisans.  The SLCLC's 1936 constitution lists its purposes as: the furtherance of the cause of freedom of speech, writing, publication, assembly and thought by all legitimate means; the protection of the legal rights of individuals in respect to such instances as may be deemed worthy; the promotion or opposition of legislation and other official action bearing upon civil liberties; and cooperation to the fullest extent possible with the American Civil Liberties Union in such of its activities as meet with the approval of the SLCLC.

The StLCLC changed its name to the American Civil Liberties Union of Eastern Missouri (ACLU/EM) in 1968. In 1971 the position of Executive Director was created to head up the workings of the ACLU/EM. The Board of Trustees conducts the affairs of the affiliate, and officers of the affiliate consisted of a President, Vice President, Secretary and Treasurer. 

On Oct. 1, 2013, the ACLU-EM became the ACLU of Missouri and has responsibility for the entire state.

Background material from:

Johnson, Donald.  The Challenge to American Freedoms (University of Kentucky Press, 1963)

Donohue, William A. The Politics of the American Civil Liberties Union.  (Transaction Books, 1985)

Lamson, Peggy. Roger Baldwin: Founder of the American Civil Liberties Union.  (Houghton Mifflin, 1976)