In the case of Norfolk & Western Railway Company et al. v. American Train Dispatchers' Association et al., 1990, the U.S Supreme Court ruled that a railroad company could not be required to arbitrate disputes over whether it had violated labor agreements by contracting out work previously performed by union members. The court held that such issues were minor disputes under the Railway Labor Act and thus subject to arbitration only if they arose from interpretation or application of an existing agreement between parties involved in dispute resolution procedures outlined in collective bargaining agreements (CBAs). In this instance, no CBA provision explicitly prohibited outsourcing; hence, there was no basis for compulsory arbitration. The decision clarified how courts should distinguish between major and minor railway labor disputes - with major ones involving formation or change of CBAs requiring more extensive negotiation processes while minor ones relating to implementation or interpretation of existing CBAs being resolved through grievance procedures.

In the dissenting opinion for Norfolk & Western Railway Company v. American Train Dispatchers' Association, Justice Blackmun argued that the majority misinterpreted the Railway Labor Act (RLA). He contended that under RLA, a carrier is obligated to maintain agreed-upon conditions until it reaches an agreement with its employees or exhausts all procedures outlined in Section 6 of RLA. The majority's decision allowed carriers to unilaterally change working conditions before exhausting these procedures, which he believed was contrary to Congress’s intent when drafting this law. Furthermore, he disagreed with the majority's view on arbitration awards and their interpretation of 'status quo'. He stated that if a dispute arises after an arbitration award has been implemented but before any changes have been made according to Section 6 notice requirements, then status quo should be defined by terms of most recent collective bargaining agreement rather than those imposed by arbitration award.