In the case of National Labor Relations Board v. Food Store Employees Union, Local 347, Amalgamated Meat Cutters & Butcher Workmen of North America, AFL-CIO (1973), the Supreme Court ruled in favor of the National Labor Relations Board (NLRB). The dispute arose when a union picketed at a grocery store to pressure it into only selling meat from unionized suppliers. The NLRB argued that this was an unfair labor practice under Section 8(b)(4) of the National Labor Relations Act because it constituted secondary boycott activity - targeting neutral parties to influence primary labor disputes. The court agreed with NLRB's interpretation and held that such conduct by unions is indeed prohibited by law as it disrupts commerce and affects parties who are not directly involved in their disputes.

In the dissenting opinion for the case of NATIONAL LABOR RELATIONS BOARD v. FOOD STORE EMPLOYEES UNION, LOCAL 347, AMALGAMATED MEAT CUTTERS & BUTCHER WORKMEN OF NORTH AMERICA, AFL-CIO (1973), Justice Douglas argued that unions should be allowed to peacefully picket in order to pressure employers into recognizing them as bargaining agents. He believed that this right was protected by the First Amendment's guarantee of free speech and assembly. Furthermore, he disagreed with the majority's interpretation of labor law which prohibited such actions unless a union had majority support among employees. In his view, this unfairly favored employers and undermined workers' rights to organize collectively for better conditions.