In the United States Supreme Court case, United Mine Workers of America v. Pennington et al., 1964, the court examined whether a labor union and large coal operators violated antitrust laws by conspiring to set high wage standards that small coal companies could not afford. The plaintiffs were small mine owners who alleged that this conspiracy was designed to drive them out of business. The defendants argued they were protected under an exemption in antitrust law for collective bargaining agreements. However, the Supreme Court held that while unions are generally exempt from antitrust liability when acting alone, they lose this protection when they conspire with non-labor groups such as businesses or employers. Therefore, if it could be proven at trial that there was indeed a conspiracy between the union and larger coal operators to price smaller competitors out of business through artificially high wages then both parties would be liable under federal anti-trust laws.

In the dissenting opinion for United Mine Workers of America v. Pennington, Justice Goldberg argued that the majority's decision was a misinterpretation of antitrust laws and labor policy. He contended that collective bargaining agreements should not be subject to antitrust scrutiny unless there is clear evidence of anti-competitive conduct beyond normal union activities. In this case, he believed no such evidence existed. Furthermore, he asserted that exempting labor unions from certain aspects of antitrust legislation does not give them carte blanche to engage in any activity they wish; rather it allows them to pursue legitimate goals through collective action without fear of legal reprisal under these laws. He also expressed concern about the potential chilling effect on future union negotiations if they were constantly under threat from antitrust litigation.