In the case of International Ladies' Garment Workers' Union, AFL-CIO v. National Labor Relations Board et al., 1960, the U.S Supreme Court ruled in favor of the National Labor Relations Board (NLRB). The dispute arose when two labor unions were competing to represent a group of workers at an apparel company. One union had already signed a contract with the employer but was later challenged by another union that claimed it represented a majority of employees and demanded recognition from management. When this demand was refused, they filed an unfair labor practice charge against both parties with NLRB which ordered for new elections to be held. This decision was appealed up to Supreme Court arguing that NLRB did not have authority under Taft-Hartley Act to order such election while there's still valid collective bargaining agreement in place unless there is substantial evidence showing dissatisfaction among employees about their current representation or misconduct on part of incumbent representative affecting its status as exclusive representative. However, court upheld NLRB's decision stating it has broad power under act not only preventing unfair practices but also taking affirmative actions promoting free choice for employees regarding their representatives.

In the dissenting opinion for INTERNATIONAL LADIES' GARMENT WORKERS' UNION, AFL-CIO, v. NATIONAL LABOR RELATIONS BOARD et al., Justice Brennan disagreed with the majority's interpretation of Section 8(b)(4)(A) of the National Labor Relations Act. He argued that this section was intended to prohibit secondary boycotts only when they were used as a weapon in labor disputes and not when they served other legitimate union objectives. In his view, the Union's picketing at Kayser-Roth was not aimed at forcing Kayser-Roth to cease doing business with Darlington but rather sought to publicize Darlington's unfair labor practices and encourage consumer pressure on Darlington itself. Therefore, he believed that such activity should be protected under federal law because it is part of unions’ efforts to improve working conditions by lawful means.