The U.S. Supreme Court case National Labor Relations Board v. Industrial Union of Marine & Shipbuilding Workers of America, AFL-CIO, et al., 1967 involved the question of whether a union's imposition and enforcement of fines on its members for crossing an "unfair labor practice" picket line during their off-duty hours violated the National Labor Relations Act (NLRA). The court ruled in favor of the National Labor Relations Board (NLRB), stating that such fines did indeed violate section 8(b)(1)(A) of NLRA which prohibits unions from restraining or coercing employees in exercising their rights under this law. This decision upheld NLRB’s power to regulate internal union affairs when they affect industrial relations stability.

In the dissenting opinion for the case of NATIONAL LABOR RELATIONS BOARD v. INDUSTRIAL UNION OF MARINE & SHIPBUILDING WORKERS OF AMERICA, AFL-CIO, et al., 1967, Justice Fortas disagreed with the majority's ruling that a union could be held responsible for its members' illegal actions during a strike. He argued that this was an unfair burden to place on unions and would undermine their ability to effectively advocate for workers' rights. Furthermore, he contended that it was not reasonable or fair to hold unions accountable for every action taken by their members during strikes because they cannot control all individual behavior. Instead, he suggested focusing on whether or not the union leadership had actively encouraged or condoned such behavior as a more accurate measure of responsibility.