In the case of Denver & Rio Grande Western Railroad Co. v. Brotherhood of Railroad Trainmen et al., 1966, the U.S Supreme Court ruled in favor of the railroad company, holding that a federal court has jurisdiction to issue an injunction against a labor union's strike when it is based on minor disputes under the Railway Labor Act (RLA). The dispute arose from disagreements over interpretation and application of collective bargaining agreements between Denver & Rio Grande Western Railroad Company and its employees' unions. The unions threatened to strike after unsuccessful negotiations with management regarding their demands for additional pay for certain work assignments which they claimed were outside their normal duties but had been performed without extra compensation. However, these claims were deemed as 'minor disputes' by RLA standards because they involved interpretation or application of existing contracts rather than negotiation for new ones; hence subjecting them to compulsory arbitration instead of strikes or lockouts.

In the dissenting opinion for Denver & Rio Grande Western Railroad Co. v. Brotherhood of Railroad Trainmen, Justice Harlan argued that the majority's decision was a departure from established principles governing labor disputes under the Railway Labor Act (RLA). He contended that while Congress intended to promote collective bargaining and peaceful resolution of disputes in this sector, it did not intend to give federal courts jurisdiction over minor grievances between railroads and their employees. Instead, these should be resolved through negotiation or arbitration as provided by RLA procedures. The majority’s ruling effectively allowed unions to circumvent these processes by bringing suit in federal court whenever they disagreed with an employer's interpretation of a collective bargaining agreement - something he believed was contrary to congressional intent when enacting the RLA.