In the case of Mandel Brothers, Inc. v. Wallace (1948), the U.S Supreme Court was tasked with determining whether a state could impose a tax on out-of-state retailers for goods delivered within its borders without violating the Commerce Clause of the Constitution. The dispute arose when Illinois imposed such a tax on Mandel Brothers, an out-of-state retailer that sold and delivered goods to customers in Illinois through mail order catalogs and traveling salesmen. The court ruled in favor of Wallace, representing Illinois Department of Revenue, upholding that states have authority to levy taxes on interstate commerce transactions if they are connected sufficiently with benefits provided by the state. It found no violation against Commerce Clause as long as there is no discrimination against interstate commerce or undue burden upon it. This decision affirmed that while states cannot impede free private trade among states under Commerce Clause protection, they can still exercise their power to ensure fair share taxation from businesses benefiting from local services like police protection or public utilities.

In the dissenting opinion for Mandel Brothers, Inc. v. Wallace, it was argued that the majority's decision to uphold a state law requiring employers to provide seats for female workers infringed upon constitutional rights and exceeded the scope of legitimate police power. The dissenting justices believed that this law was discriminatory as it only applied to women and not all employees regardless of gender. They also contended that there were no substantial health reasons or other justifications provided by the state which would warrant such an intrusion into private business practices. Furthermore, they expressed concern about potential economic consequences on businesses due to additional costs associated with compliance with this regulation.