In the 1943 case United States et al. v. County of Allegheny, the U.S Supreme Court ruled in favor of the federal government and against Allegheny County, Pennsylvania. The dispute arose over whether or not a county could tax federally-owned land that was being used for private commercial purposes under a lease agreement with a private company. The court held that such taxation constituted an unconstitutional interference with federal supremacy because it effectively imposed a tax on property owned by the United States government itself, which is immune from state and local taxation under principles of intergovernmental immunity embodied in Supremacy Clause of Constitution (Article VI). This decision reinforced the principle that states cannot interfere with or impede operations of Federal Government through imposition of taxes on its properties.

The dissenting opinion in the United States v. County of Allegheny case argued that the majority's decision to allow federal government intervention in local tax matters was a dangerous overreach of power. The dissenters believed that this ruling undermined states' rights and threatened the balance between state and federal powers established by the Constitution. They contended that allowing such interference could lead to an imbalance, with potential for misuse or abuse of authority by federal entities at expense of state autonomy. Furthermore, they expressed concern about setting a precedent where any perceived inequality could justify federal intrusion into traditionally state-controlled areas like taxation policy, potentially leading to further erosion of states' rights in future cases.