In the 1972 case of Otter Tail Power Co. v. United States, the Supreme Court ruled in favor of the U.S., upholding a lower court's decision that Otter Tail Power Company had violated antitrust laws by refusing to sell power at wholesale rates to municipal corporations seeking to establish their own electric systems and by denying them access to its transmission lines. The company argued it was not obligated under federal law (the Federal Power Act) to do so, but this argument was rejected by the court which held that such refusal constituted an illegal use of monopoly power aimed at stifering competition. This ruling affirmed that utility companies could be subject to antitrust regulations and set a precedent for future cases involving monopolistic practices within public utilities.

In the dissenting opinion for Otter Tail Power Co. v. United States, Justice Rehnquist argued that the majority's decision to apply antitrust laws to a regulated industry was misguided and could potentially disrupt regulatory schemes established by Congress. He contended that the Federal Power Commission (FPC) had exclusive jurisdiction over wholesale electricity transactions and therefore, it should be left up to them - not courts - to decide whether refusal of service constitutes an abuse of monopoly power. Furthermore, he disagreed with the majority's interpretation of 'public interest' in relation to antitrust law enforcement within regulated industries like utilities; arguing instead that public interest is better served when regulatory agencies are allowed full control over their respective domains without interference from generalist courts applying broad competition principles.