After World War II, the Committee for Amnesty led a three-year campaign to obtain amnesty for the 6,000 US conscientious objectors (COs) sentenced to prison for their refusal to participate in the war. In addition, the Committee for Amnesty sought to win freedom for those COs who remained in prison long after the war ended. As convicted felons, prison COs were ‘second-class citizens’ deprived of their full civil rights, including the right to vote. During World War II, social actionist COs staged dramatic work and hunger strikes to protest racism, censorship, conscription, and the myriad policies that dehumanized prison and gutted the original vision of Civilian Public Service, a program of alternative nonmilitary service. After the war, these radicalized COs applied the techniques of Gandhian nonviolent direct action, developed in prison and Civilian Public Service camps, to advance peace and justice — most notably in the anti-war, civil rights, environmental, anti-nuclear, and civil liberties movements. The amnesty campaign, which was initiared by prison COs and their friends and relatives, represented one of the first examples of this militant postwar CO activism. The Committee for Amnesty demonstrates the impact of World War II COs on the War Resisters League and the postwar radical pacifist movement. These COs — militant, absolutist-orientated, creative, and committed to direct action — shaped the methods and goals of the amnesty campaign, dividing the War Resisters League in the process. The amnesty campaign illustrates the postwar grass-roots social activism of World War II COs, their contribution to civil liberties and social reform movements, and their impact on the postwar radical pacifist movement.