In the case of Shipman et al., trading as Shipman Brothers, et al. v. DuPre et al., 1949, the Supreme Court was asked to consider whether a South Carolina state law that imposed a license tax on every person engaged in selling beer was constitutional under the Fourteenth Amendment's Equal Protection Clause. The plaintiffs argued that they were being discriminated against because wholesalers and retailers who sold both wine and beer only had to pay one license fee while those who solely sold beer had to pay an additional fee for their licenses. However, the court ruled in favor of DuPre stating that there is no denial of equal protection when different classes are taxed differently if it is based on some reasonable ground or difference between them which bears a just relation to the attempted classification for taxation purposes.

In the dissenting opinion for Shipman et al., Trading as Shipman Brothers, et al. v. DuPre et al., it was argued that the majority's decision to uphold a South Carolina law prohibiting out-of-state beer manufacturers from selling directly to retailers in the state infringed upon interstate commerce rights protected by the U.S. Constitution. The dissenters believed that this law unfairly discriminated against non-local businesses and gave an unfair advantage to local wholesalers who were not subject to such restrictions, thereby creating a monopoly-like situation within South Carolina's beer market which could potentially lead to higher prices for consumers and less competition among suppliers. They also contended that there was no substantial reason or public interest served by this restriction on direct sales other than protecting local business interests at the expense of out-of-state competitors, making it unconstitutional under Commerce Clause jurisprudence.