The U.S. Supreme Court case Florida v. Mellon, Secretary of the Treasury, et al., 1926 revolved around a dispute over inheritance tax laws. The state of Florida filed suit against Andrew W. Mellon, then Secretary of the Treasury, and other federal officials to prevent them from collecting federal estate taxes in Florida on grounds that it violated states' rights under the Tenth Amendment and was an infringement upon its sovereignty as a state by imposing double taxation on its citizens who were already subjected to state-level inheritance taxes. However, the Supreme Court dismissed this claim stating that there is no constitutional prohibition against double taxation by both federal and state governments since they are separate entities with distinct taxing powers granted by different sovereigns (the people for Federal government and State respectively). Therefore, it upheld the right of Congress to levy estate taxes irrespective of any similar charges imposed at a state level.

In the dissenting opinion for Florida v. Mellon, Secretary of the Treasury, et al., Justice McReynolds expressed his disagreement with the majority's ruling that a state could not challenge federal tax laws on behalf of its citizens. He argued that states should have standing to sue when they believe their residents are being unfairly taxed by the federal government. According to him, if states cannot protect their citizens from what they perceive as unconstitutional taxation then it undermines their sovereignty and weakens our system of federalism. Furthermore, he contended that this case was about more than just taxes; it was about preserving a balance between state and national power in order to safeguard individual liberty against potential overreach by either level of government.