In the United States v. Parke, Davis & Co., 1959 case, the U.S Supreme Court ruled against pharmaceutical company Parke, Davis & Co., finding them guilty of violating antitrust laws. The court held that the company had engaged in illegal price-fixing activities by coercing wholesalers and retailers to agree on set prices for its products. This was achieved through a combination of direct communications and indirect pressure tactics such as refusing to supply products unless their pricing policies were adhered to. The ruling clarified that any attempts by a manufacturer to impose fixed resale prices on distributors or retailers constituted an unlawful restraint of trade under the Sherman Act - even if it involved unilateral actions rather than explicit agreements between parties.

The dissenting opinion in the United States v. Parke, Davis & Co. case argued that the majority's decision expanded antitrust laws beyond their intended scope and purpose. The dissent contended that Parke, Davis & Co.'s actions did not constitute an illegal restraint of trade under the Sherman Act because they were merely attempting to maintain a fair price for their product across all retailers. They believed this was within their rights as a manufacturer and should not be considered anti-competitive behavior or market manipulation. Furthermore, they disagreed with the majority's interpretation of "combination" or "conspiracy", arguing it was too broad and could potentially criminalize normal business practices if left unchecked.