What impact did McCulloch v. Maryland have?

• A. It established the supremacy of the national government over the states via the Necessary and Proper Clause
• B. It ended the use of the Necessary and Proper Clause
• C. It limited Congress's taxing power
• D. It expanded rights of state governments in taxation.

Answer: (A)

The central idea is federal supremacy and the reach of implied powers through the Necessary and Proper Clause. McCulloch v. Maryland held that Congress could create a national bank as an implied power necessary to execute its enumerated fiscal powers, and that a state cannot tax that federal instrument because federal law is supreme over state law. This ruling uses the Supremacy Clause to say that national authority stands over conflicting state actions, and it confirms that the Necessary and Proper Clause allows Congress to take actions not explicitly listed if they are appropriate to carry out its constitutional duties.

That’s why this option is the best fit: it captures the essential outcome—the strengthening of federal supremacy over states through a flexible interpretation of the Necessary and Proper Clause. The other ideas misstate what happened: the decision did not end the Necessary and Proper Clause or limit Congress’s taxing power; it did not expand state taxation rights—on the contrary, it curbed state power to tax federal instruments.