In the case of Purity Extract and Tonic Company v. Lynch, 1912, the U.S Supreme Court was tasked with determining whether a state law that prohibited the sale of alcohol violated interstate commerce regulations. The Purity Extract and Tonic Company had been selling non-intoxicating beer in Alabama when it was charged under a state law prohibiting such sales. The company argued that since their product did not cause intoxication, it should not be classified as an alcoholic beverage under Alabama's prohibition laws. Furthermore, they claimed this restriction interfered with interstate commerce rules because their product was manufactured out-of-state before being sold in Alabama. The Supreme Court ruled against Purity Extract and Tonic Company stating that states have broad powers to regulate alcohol within their borders without violating federal commerce laws. They held that even if a beverage does not cause intoxication but contains some amount of alcohol (as did the tonic), it could still fall under state regulation or prohibition policies on alcoholic beverages.

In the dissenting opinion for Purity Extract and Tonic Company v. Lynch, it was argued that the state of Alabama's law prohibiting the sale of medicines containing more than a certain percentage of alcohol was unconstitutional. The justice believed that this law violated both due process and equal protection clauses by unfairly targeting out-of-state businesses while exempting local ones from similar restrictions. He also contended that such laws were not within a state's police power as they did not serve to protect public health or safety but rather acted as an arbitrary restriction on commerce. Furthermore, he disagreed with the majority’s view about states' rights in regulating interstate commerce, arguing instead for federal supremacy in these matters based on constitutional principles.