In the 1946 case of Order of Railway Conductors of America et al. v. Swan et al., the United States Supreme Court ruled on a dispute between a railway company and its employees' union over seniority rights for conductors who had served in World War II. The court held that under the Selective Training and Service Act, returning veterans were entitled to their pre-service jobs with full seniority, including any promotions they would have received if they hadn't left for military service. This meant that some conductors who had not served in the war found themselves demoted upon their colleagues' return from service, which led them to sue both their employer and union for violating collective bargaining agreements by failing to protect their seniority rights. However, the Supreme Court upheld lower courts’ decisions favoring veterans' reemployment rights over contractual obligations between employers and unions.

In the dissenting opinion for the case Order of Railway Conductors of America et al. v. Swan et al., Justice Frankfurter argued that the majority's decision to allow a union to unilaterally change an existing collective bargaining agreement was fundamentally flawed and contrary to established labor law principles. He contended that such unilateral changes undermine stability in labor relations, which is one of the primary goals of collective bargaining agreements. Furthermore, he asserted that allowing unions to make these types of changes without employer consent or negotiation could lead to arbitrary and capricious actions by unions, potentially harming both employers and employees alike. Therefore, he disagreed with the majority's interpretation of Section 6 notice requirements under The Railway Labor Act as permitting such unilateral amendments by unions.