In the case of National Labor Relations Board v. Great Dane Trailers, Inc., the Supreme Court ruled in favor of the National Labor Relations Board (NLRB). The dispute arose when Great Dane Trailers implemented a policy that denied accumulated vacation benefits to striking employees while granting them to non-striking workers. The NLRB argued this was an unfair labor practice under Section 8(a)(3) and (1) of the National Labor Relations Act because it discriminated against union members for their participation in a lawful strike. In its decision, the court held that such discrimination constituted prima facie evidence of an anti-union animus and thus violated federal law. It further stated that even if there were legitimate business reasons for implementing such policies, they would not justify actions inherently destructive towards employee rights unless they served vital employer interests which could not be achieved through less harmful means.

In the dissenting opinion for the National Labor Relations Board v. Great Dane Trailers, Inc., it was argued that there was no substantial evidence to support the majority's conclusion that Great Dane had violated Section 8(a)(3) of the National Labor Relations Act by discriminating against striking employees in its distribution of vacation pay. The dissent pointed out that all employees who worked during a certain period were eligible for vacation pay, regardless of whether they later went on strike or not. Therefore, this policy did not inherently discriminate against strikers but rather rewarded those who continued working during a specific time frame. Furthermore, it was noted that such policies are common and generally accepted in labor relations practice and should be considered lawful unless proven otherwise with clear evidence of discriminatory intent – which wasn't provided in this case according to the dissenting justices.