In the case of Monsanto Co. v. Spray-Rite Service Corp., the U.S. Supreme Court was tasked with determining whether or not Monsanto Company had violated antitrust laws by allegedly setting minimum resale prices for its products and terminating a distributor, Spray-Rite Service Corporation, who did not comply with these prices. The court ruled in favor of Spray-Rite, stating that there must be direct evidence of an agreement to set prices between a manufacturer and its distributors to prove a violation under Section 1 of the Sherman Act (which prohibits business activities that reduce competition). In this case, while there were communications about pricing between Monsanto and its distributors, it was deemed insufficient as proof for such an agreement because manufacturers are allowed to communicate with their distributors about price levels without violating antitrust laws.

The dissenting opinion in the Monsanto Co. v. Spray-Rite Service Corp case argued that the majority's decision to require direct evidence of an agreement for a vertical price-fixing claim was too restrictive and inconsistent with precedent. The dissent contended that circumstantial evidence should be sufficient to prove such claims, as it is in other antitrust cases. They also expressed concern that this higher standard of proof would make it more difficult for plaintiffs to succeed in these types of cases, potentially undermining enforcement of antitrust laws designed to protect competition and consumers from anti-competitive practices.