McCulloch v. Maryland was a landmark decision by the Supreme Court of the United States. The state of Maryland had attempted to impede operation of a branch of the Second Bank of the United States by imposing a tax on all notes of banks not chartered in Maryland. The Court invoked the Necessary and Proper Clause of the Constitution, which allowed the Federal government to pass laws not expressly provided for in the Constitution’s list of express powers, provided those laws are in useful furtherance of the express powers of Congress under the Constitution.
This case established two important principles in constitutional law. First, the Constitution grants to Congress implied powers for implementing the Constitution’s express powers, in order to create a functional national government. Second, state action may not impede valid constitutional exercises of power by the Federal government.