But this mainstream acceptance came with a price. Malin failed to adequately protect Americans targeted by Joseph McCarthy and others during the second Red Scare, and even went so far as to leak private ACLU documents to J. Edgar Hoover in exchange for FBI surveillance information on political affiliations of Board members. Malin had presumably hoped to avoid the embarassment of having any ACLU board members outed as communists by McCarthy.
The defining conflict of the ACLU during the 1950s was between Malin and Corliss Lamont, a member of the ACLU Board of Directors who had written a 1952 book titled The Myth of Soviet Aggression. Although Lamont was not a member of the American Communist Party, he was targeted by McCarthy and received no substantial support from the ACLU. He resigned in protest to form the Emergency Civil Liberties Union (ECLU), which was devoted entirely to fighting the McCarthy agenda--ultimately winning several high-profile suits against the government that the ACLU leadership lacked the courage to pursue.
By the end of Malin's tenure, the ACLU had become a largely irrelevant, moderate force in American policy. Beloved by many but feared by few, it took the correct positions on some issues--most notably filing an amicus brief against school segregation in the landmark Brown v. Board of Education (1954)--but was hardly the fearsome defender of civil liberties that it had once been, and would soon become again.