In the 1940 case of American Federation of Labor et al. v. Swing et al., the U.S Supreme Court ruled on a dispute between labor unions and an employer over picketing rights. The unions, including the American Federation of Labor (AFL), were protesting against Swing, a non-union company, by peacefully picketing outside their premises to dissuade potential customers from patronizing them in order to pressure them into recognizing and bargaining with the union. However, Illinois state law prohibited such actions as it was seen as obstructing business without any direct economic interest involved for those participating in protest activities. The court held that this prohibition violated First Amendment rights to freedom of speech and assembly since peaceful picketing is a form of expression protected under these constitutional provisions regardless if there's no immediate economic concern for protesters or not. This decision marked an important precedent affirming labor's right to engage in peaceful protests even when they are not directly economically affected parties.

In the dissenting opinion for the American Federation of Labor v. Swing case, Justice Roberts argued that labor unions should have the right to peacefully picket businesses as a form of free speech. He believed that this was an essential part of collective bargaining and union activity, which are protected by law. Furthermore, he disagreed with the majority's interpretation of "coercion," arguing that peaceful picketing does not inherently involve coercion or intimidation. Instead, it is simply a way for workers to publicly express their grievances and demands in order to negotiate better working conditions or wages with their employers. Therefore, according to Justice Roberts' dissenting view, banning such activities would infringe upon workers' constitutional rights.