In the case of United Mine Workers of America, District 12 v. Illinois State Bar Association et al., the U.S. Supreme Court ruled in favor of the United Mine Workers (UMW) union in 1967. The Illinois State Bar Association and other plaintiffs had filed a lawsuit against UMW, alleging that it was engaging in unauthorized practice of law by providing legal services to its members through salaried attorneys employed by the union's welfare and retirement fund. The court held that such provision did not constitute unauthorized practice as long as these lawyers were responsible only to their clients -the miners- and not to their employer -the Union-. This decision affirmed unions' rights to provide legal assistance for their members without violating state laws prohibiting non-lawyers from practicing law.

In the dissenting opinion for the United Mine Workers of America, District 12 v. Illinois State Bar Association case, Justice William O. Douglas argued that unions should be allowed to provide legal services to their members as part of collective bargaining agreements without being accused of unauthorized practice of law. He believed this was a matter between an employee and his union and did not involve any public interest that would justify interference by state bar associations or courts. Furthermore, he contended that denying unions the right to offer such services could potentially deprive workers of valuable legal assistance in disputes with employers over wages, working conditions, or other employment issues due to financial constraints or lack of access to competent counsel. In essence, Justice Douglas saw this prohibition as an infringement on labor rights and a barrier preventing ordinary workers from obtaining justice.