By the 1950s most of the rights associations that had emerged in the 1930s and 1940s were largely inactive or defunct. The Vancouver branch of the Canadian Civil Liberties Union, Civil Liberties Association of Winnipeg, Ottawa Civil Liberties Association and Montreal Civil Liberties Association had quickly dissolved. The Association for Civil Liberties had been formed out of members from the Civil Liberties Association of Toronto eager to create a national civil liberties association headquartered in Toronto. Among the leadership were Toronto lawyers Irving Himel and Andrew Brewin (future New Democratic Party MP), as well as B.K. Sandwell (editor of Saturday Night) and Charles Millard of the United Steelworkers of America. They expended most of their energies combating restrictive covenants, censorship and police powers while agitating for provincial Fair Employment Practices legislation and a bill of rights. Sandwell, Himel and Brewin were also responsible for creating the Committee for a Bill of Rights in 1946 as an adjunct to the CLAT. Their committee presented the Minister of Justice with a petition of 200 ‘respectable’ members of the community from across the country calling for a bill of rights in 1946, and in 1951 organized a delegation to Prime Minister St. Laurent representing 200 people and 50 organizations.

According to Ross Lambertson: "As many as 300 people turned up at the founding meeting of the ACL, which chose as its first chair R.S.K Seeley, the Provost and Vice-Chancellor of Trinity College. Like its antecedent, the ACL was a 'respectable' organization with many CCF members but with liberals to give it a non-partisan cast The chair of its committee for a bill of rights was B.K. Sandwell, and several of the vice-presidents were well-known either as human rights activists or members of the political/legal/intellectual elite: Rabbi Feinberg, Charles Millard, Malcolm Wallace, Joseph Sedgwick, Harold M. Cassidy, and Mrs. W.L. Grad. In addition, the organization's first treasurer was W.P. Jenkins, a Unitarian Minister, and its Council included several other well-known noncommunist members of the Canadian human rights policy community, including Andrew Brewin, James Finlay, George Tatham, E. Corbett, and George Tanaka, as well as the Liberal MP David Croll and a number of CCF politicians: E.B. Joliffe, Eamon Park, and Lloyd Fell." (Lambertson, 316).

One of the requirements for membership in the Association for Civil Liberties was not having membership in any other civil liberties association, a measure designed to exclude communists. Civil liberties advocates were bitterly divided during this period between communists and social democrats/liberals. While the ACL was led by the latter, communists formed the League for Democratic Rights which functioned as a rival national civil liberties association. The ACL was essentially defunct by the late 1950s except for the occasional pronouncements from Toronto lawyer Irving Himel. Himel would later go on to found the Canadian Civil Liberties Association in 1964.