In the 1941 case of Curry, Commissioner of Revenue of Alabama v. United States et al., the Supreme Court ruled on a dispute involving taxation and interstate commerce. The state of Alabama had imposed a tax on gross receipts from railroad freight transportation within its borders, which included both intrastate and interstate shipments. The Louisville & Nashville Railroad Company challenged this tax as it applied to their interstate operations, arguing that it violated the Commerce Clause by placing an undue burden on interstate commerce. They also contended that they were being discriminated against because other forms of transportation (like trucks) weren't taxed in the same way. The Supreme Court sided with the railroad company, ruling that while states have some power to tax businesses operating within their borders—even those involved in interstate commerce—this particular tax was discriminatory and therefore unconstitutional under the Commerce Clause. This decision reinforced principles limiting state interference with federal regulation over inter-state trade.

In the dissenting opinion for Curry, Commissioner of Revenue of Alabama v. United States et al., Justice Frank Murphy argued that the majority's decision was a misinterpretation of both constitutional law and precedent. He contended that the federal government did not have an inherent right to immunity from state taxation, but rather this privilege must be explicitly granted by Congress. In his view, there were no such congressional provisions in place at the time regarding interstate railway mail cars owned by private companies but used under contract with the U.S Postal Service. Therefore, he believed these properties should be subject to state tax laws just like any other privately-owned property within a given state’s jurisdiction. Furthermore, he warned against overextending federal power at states' expense as it could upset our system's delicate balance between central authority and local autonomy.