In the case of Simpson v. Union Oil Co. of California, 1963, the U.S Supreme Court ruled in favor of plaintiff Robert L. Simpson who was a service station operator for Union Oil Company (Unocal). The court found that Unocal had violated antitrust laws by engaging in price fixing and restricting competition through its "consignment" agreements with dealers like Simpson. These agreements allowed Unocal to control retail prices at stations operated by independent dealers which effectively eliminated any form of competitive pricing among these retailers. This practice was deemed illegal under the Sherman Antitrust Act as it restrained trade and suppressed competition within the market place.

In the dissenting opinion for Simpson v. Union Oil Co. of California, it was argued that the majority's decision failed to consider important aspects of antitrust law and its implications on business practices. The dissent highlighted that there was no evidence presented in court showing any adverse effects on competition due to Union Oil’s consignment agreement with independent dealers like Simpson. They also pointed out that such agreements are common practice in many industries and can often be beneficial by allowing small businesses access to products they might not otherwise afford or have access to, thereby promoting competition rather than stifling it as alleged by the plaintiff. Furthermore, they contended that if every vertical arrangement were considered a violation of antitrust laws without clear proof of anti-competitive conduct or effect, this would create an undue burden on businesses and potentially harm economic growth.