Lomax was a supporter of several civil rights organizations, including the Congress of Racial Equality (CORE), the Student Nonviolent Coordinating Committee (SNCC), and the Southern Christian Leadership Conference (SCLC). In 1968, he signed the "Writers and Editors War Tax Protest" pledge, vowing to refuse tax payments in protest against U.S. involvement in the Vietnam War.Writers and Editors War Tax Protest". January 30, 1968. New York Post.
