The U.S. Supreme Court case Milk Control Board v. Eisenberg Farm Products, 1938, revolved around the constitutionality of Pennsylvania's Milk Control Act of 1937 which allowed a state board to fix minimum prices for milk and dairy products sold within the state. The defendant, Eisenberg Farm Products, was charged with selling milk below these fixed prices in violation of the act. They argued that this law violated their rights under both federal and state constitutions by depriving them of property without due process and denying equal protection under laws as it exempted certain classes from its provisions. However, the court upheld Pennsylvania’s right to regulate milk prices citing that such regulation was not arbitrary or discriminatory but rather necessary for public welfare given how vital milk is as a food product; thus it did not violate constitutional rights. Furthermore, they stated that any exemptions were reasonable classifications based on differences in circumstances among different groups involved in production/distribution processes.

In the dissenting opinion for Milk Control Board v. Eisenberg Farm Products, it was argued that the Pennsylvania Milk Control Act of 1937 did not violate the Commerce Clause of the U.S. Constitution as majority opined. The dissenting justices believed that this case should have been viewed from a broader perspective, considering both intrastate and interstate commerce in milk as part of an integrated system which needed to be regulated for public welfare reasons such as maintaining stable markets and ensuring fair prices for producers and consumers alike. They also disagreed with the majority's interpretation of Baldwin v G.A.F Seelig Inc., arguing that it didn't prohibit states from regulating their own dairy industries but rather prevented them from imposing their regulations on other states' businesses without consent or reciprocity agreements in place. Furthermore, they contended that if every state followed suit after Pennsylvania by enacting similar legislation then there would be no conflict between different jurisdictions hence no violation against Commerce Clause could occur under such circumstances.