In the 1939 case of Ethyl Gasoline Corporation et al. v. United States, the Supreme Court ruled on a matter involving antitrust laws and patent rights. The Ethyl Gasoline Corporation held patents for tetraethyl lead, an additive used to improve gasoline performance in internal combustion engines. They licensed these patents exclusively to three major oil companies while refusing licenses to other smaller competitors, which led the government to file suit alleging violations of antitrust laws. The court found that although patent holders generally have significant control over their inventions' use and sale, this power does not extend beyond what is necessary for protecting the invention itself; it cannot be used as a means of restraining competition unlawfully in unpatented materials or commodities. Therefore, by using its patent monopoly over tetraethyl lead additives as leverage to restrict trade within the broader market for gasoline — an item outside its patented invention — Ethyl was deemed guilty of violating federal anti-trust law.

The dissenting opinion in the Ethyl Gasoline Corporation v. United States case argued that the majority's decision to uphold the Federal Trade Commission's cease and desist order was incorrect. The dissenters believed that there was no substantial evidence proving that Ethyl Gasoline Corporation had engaged in unfair methods of competition, which is a requirement for issuing such an order under Section 5 of the Federal Trade Commission Act. They also disagreed with how broadly "unfair methods of competition" were interpreted by both FTC and Supreme Court, arguing it could lead to arbitrary enforcement actions against businesses based on subjective judgments about what constitutes fair or unfair practices rather than objective legal standards. Furthermore, they contended that even if Ethyl did engage in anti-competitive behavior as alleged, this should be addressed through antitrust laws specifically designed to regulate market competition instead of using FTC Act provisions intended for consumer protection purposes.