The emergence of the American Federation of Labor in the 1880s and its ideology of voluntarism or “business unionism” transformed the mainstream American labor movement. Voluntarism, however, had little impact on the formation of the pre-New Deal labor policy. I suggest that members of the progressive movement developed “responsible unionism” as an alternative to “business unionism” and that it was the progressives' alternative that shaped later developments in labor policy. (1) Progressive state and federal court judges relied on the principles of agency, a fiduciary term, to make unions competent contracting parties and enforce collective trade agreements. (2) Although the AFL had long lobbied for anti-injunction legislation sup ported by an underlying ideology of voluntarism, the progressive Republican-Democratic coalition that engineered passage of the Norris-LaGuardia Anti-Injunction Act of 1932 based the legislation on their notion of “responsible unionism.” These progressives interwove the principles of agency into the act. As a result, rather than withdrawing the American state from labor-management relations, the act caused unions to begin to lose their status as private, voluntary associations, thus creating the foundation for the construction of the statist regulatory apparatus, the National Labor Relations Board, during the New Deal.