In the 1952 case of Automatic Canteen Company of America v. Federal Trade Commission, the Supreme Court ruled in favor of the Federal Trade Commission (FTC). The FTC had accused Automatic Canteen Company, a large vending machine operator, of violating antitrust laws by acquiring two smaller competitors and thereby reducing competition. The company argued that it was not in violation because its market share remained small even after these acquisitions. However, the court held that any acquisition which reduces competition or tends to create a monopoly is prohibited under Section 7 of the Clayton Act regardless if it leads to dominance or not. This ruling clarified how this law should be interpreted and applied with respect to mergers and acquisitions.

In the dissenting opinion for Automatic Canteen Company of America v. Federal Trade Commission, it was argued that the majority's decision to uphold FTC's cease and desist order against Automatic Canteen was incorrect. The dissenting justices believed that there wasn't substantial evidence proving that Automatic Canteen had engaged in unfair methods of competition or created a monopoly in violation of Section 5 of the Federal Trade Commission Act. They contended that while some aspects of Automatic Canteen’s business practices may have been aggressive, they were not illegal or harmful to competition overall. Furthermore, they disagreed with FTC’s broad interpretation and application of its powers under Section 5, cautioning against using this section as an all-encompassing tool to regulate any business practice deemed undesirable by FTC without clear legislative intent from Congress.