When the Supreme Court ruled that a state could not tax the Bank of the United States in McCulloch v. Maryland, it said that when a state law conflicts with a federal law, the state law should be deemed invalid. This exemplifies the application of the:

Supremacy clause

Explanation: The supremacy clause as defined in the United States constitution holds that all federal laws, constitution or treaties constitutes the Supreme law of the land that is federal laws are the principal laws of the nation and therefore outweighs any negating or conflicting state laws.

In the McCulloch v Maryland case, involving a national bank and the state of Maryland over the legality of the tax imposed on the bank, where the Supreme Court ruled in favor of McCulloch that a state could not tax a national bank. This ruling purely shows the supremacy of federal laws over conflicting state laws.

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