Between the Great War and Pearl Harbor, conservative labor leaders declared themselves America's "first line of defense" against Communism. In this surprising account, Jennifer Luff shows how the American Federation of Labor fanned popular anticommunism but defended Communists' civil liberties in the aftermath of the 1919 Red Scare. The AFL's "commonsense anticommunism," she argues, steered a middle course between the American Legion and the ACLU, helping to check campaigns for federal sedition laws. But in the 1930s, frustration with the New Dealorder led labor conservatives to redbait the Ro.