In the 1956 case Morey v. Doud, the Supreme Court of the United States ruled that an Illinois statute violated the Equal Protection Clause of the Fourteenth Amendment because it exempted a single named company from regulation while subjecting all other similar businesses to regulatory control. The law in question was designed to regulate companies selling money orders, but specifically excluded "The American Express Company" from its purview. The court held this as unconstitutional on grounds that there was no rational basis for treating one company differently than others engaged in identical business activities. This decision is significant as it established precedent regarding economic legislation and equal protection under law, emphasizing that laws must apply equally and cannot favor certain entities without sufficient justification.

The dissenting opinion in the case of Morey v. Doud, argued that the majority's decision was inconsistent with previous rulings on equal protection under the Fourteenth Amendment. The justices contended that Illinois' law exempting a single company from regulation did not violate equal protection principles because it could be justified by unique characteristics of this business or public interest considerations. They asserted that courts should defer to legislative judgment unless there is clear evidence of arbitrary discrimination and pointed out inconsistencies in how the court had applied this standard in different cases. Furthermore, they expressed concern about potential implications for other state laws granting exclusive privileges or exemptions based on specific circumstances or policy objectives.