In the 1920 case of Maguire et al. v. Reardon et al., the Supreme Court was asked to determine whether a San Francisco ordinance that required laundries within certain districts to be housed in buildings made of brick or stone violated the Fourteenth Amendment's Equal Protection Clause. The plaintiffs, who operated a laundry business in a wooden building, argued that this law unfairly targeted them and others like them while favoring those who could afford more expensive construction materials. However, the court ruled against them, stating that such regulations were within local government's police power if they had reasonable grounds for believing it would promote public safety and welfare - in this case by reducing fire hazards associated with laundry operations.

In the dissenting opinion for Maguire et al. v. Reardon et al., Justice McReynolds expressed his disagreement with the majority's decision to uphold a San Francisco ordinance that required laundries within certain districts of the city to be housed in buildings constructed of brick or stone. He argued that this law was arbitrary and unreasonable, infringing upon property rights without due process of law as protected by the Fourteenth Amendment. He contended that there was no substantial relation between requiring laundries to be built from specific materials and public health, safety, morals or general welfare - which are usually considered legitimate grounds for such regulations under police power. Furthermore, he pointed out inconsistencies in how these requirements were applied across different industries within similar fire risk categories; other businesses using large boilers weren't subject to same restrictions as laundries.