In the 1958 case of Plumbers, Steamfitters, Refrigeration, Petroleum Fitters and Apprentices of Local 298 v. County of Door et al., the Supreme Court ruled on a dispute between a labor union and county officials over whether or not certain work could be performed by non-union workers. The union argued that only its members should be allowed to perform this work under an existing collective bargaining agreement. However, the county contended that it had no obligation to honor such agreements when hiring for public works projects. The court sided with the county officials in their argument that they were not bound by private sector labor agreements when making decisions about public employment contracts. This decision upheld lower court rulings which found in favor of the defendants (the County), stating there was no violation of federal law as claimed by plaintiffs (the Union). It affirmed counties' rights to make independent decisions regarding employment practices without being constrained by private sector collective bargaining agreements.

The dissenting opinion in the case of Plumbers, Steamfitters, Refrigeration, Petroleum Fitters and Apprentices of Local 298 v. County of Door argued that the majority's decision was a departure from established precedent regarding labor disputes. The dissenters believed that the National Labor Relations Act (NLRA) preempted state law in this area and thus disagreed with the majority's ruling which allowed states to regulate certain aspects of labor relations not covered by federal law. They contended that such an interpretation could lead to inconsistent regulations across different states thereby undermining national uniformity in labor policy as intended by Congress through NLRA. Furthermore, they expressed concern over potential infringement on workers' rights due to varying state laws and emphasized their belief in maintaining strong federal oversight for protection against possible abuses or exploitation within local jurisdictions.