In 1940, the Committee to Defend America by Keeping Out of War sponsored an Emergency Peace Mobilization conference held in Chicago (Illinois) from August 31st to Sept. 2nd. It was attended by over 20,000 people, including 6,000 delegates from religious, labor, youth, farm and other organizations. Out of this conference came the American Peace Mobilization, a nonprofit organization which aimed to "keep us out of war and . . . preserve and extend our democracy." It was set up in Washington (District of Columbia), with the Rev. John B. Thompson as the national chair; Theodore Dreiser, Congressman Vito Marcantonio, Jack McMichael, Reid Robinson and Katherine Terrill as vice-chairs; Frederick Vanderbilt Field as executive secretary; and Marion Briggs as administrative secretary. National Council members included Carl Sandburg, Richard Wright and Langston Hughes. Area councils were set up in various locations to coordinate the efforts of local peace clubs. The national office was moved to New York City (New York) on February 10, 1941, though its legislative office remained in Washington.
Over the months of its existence, the APM -- through its literature, lobbying efforts, and conferences -- continued to press for nonintervention in the war, and advocated for economic liberties and well-being for all, repeal of anti-alien legislation, labor's right to organize and strike, and full civil rights for Negroes, among others. From May 9 - June 21, 1941, it sponsored a peace vigil in which 1,784 persons picketed the White House, for a total of 1,029 hours. Germany invaded the Soviet Union on June 22nd; on the same day the APM changed its name to "American People's Mobilization," adopted the slogan "For Victory Over Fascism,” and began to advocate for aid to Great Britain, the Soviet Union and all peoples fighting Nazi Germany. By October 1941, the APM was no longer in existence.