The Cleveland May Day riots of 1919 were a series of violent demonstrations that occurred throughout Cleveland, Ohio on May 1 (May Day), 1919. The riots occurred during the May Day parade organized by Socialist leader Charles Ruthenberg, of local trade unionists, socialists, communists, and the Industrial Workers of the World (IWW) to protest against the conviction of Eugene V. Debs and American intervention in the Russian Civil War against the Bolsheviks.