Clayton Van Lydegraf (May 6, 1915 – March 30, 1992)^[1] was a writer and activist of significant influence on the New Left in the 1960s. He served as Secretary of the Communist Party in Washington State in the late 1940s.^[2][3]

This article relies excessively on references to primary sources. (March 2008)

Van Lydegraf served as a leader of the Progressive Labor Party (United States) in Washington state in the 1960s before being expelled in the Spring of 1967.^[4] During this time, and expanding on his Old Left background, Van Lydegraf was involved with young Seattle activists by 1966. His articles "The Movement and the Workers" and "The Object is to Win" were particularly influential. This latter is a noteworthy piece in the development of the ideas of the Weather Underground.

Over the years, he was active in a number of groups and causes including the Communist Party, the Progressive Labor Party, the Peace and Freedom Party, Draft Resistance- Seattle, Students for a Democratic Society (SDS), American Friends Service Committee, Anti-Fascist Front, Seattle Committee to End the War in Vietnam, and trade unions. He was also an advocate of working class power, Marxism, revolutionary organization, and the Black Panthers. He took part in the preparations for the jailbreak of Timothy Leary while in the Weatherman organization but was privately critical of the action.^[5]