What aspect of federalism was affirmed in the decision of McCulloch v. Maryland?

The decision in McCulloch v. Maryland affirmed that federal powers are superior to state powers, which is a foundational principle of the Constitution known as the supremacy clause. This case specifically addressed the conflict between state and federal authority when the state of Maryland attempted to tax the Second Bank of the United States. The Supreme Court ruled that Congress had the authority to create the bank under the Necessary and Proper Clause, and it also determined that states could not impose taxes on federal institutions, as doing so would undermine federal authority.

The ruling established that federal law takes precedence over state law when the two are in conflict, reinforcing the idea that the federal government holds superior power in certain areas designated by the Constitution. This marked a significant expansion of federal authority and clarified the relationship between state and federal governments, thereby solidifying the principle that the federal government operates within its own sphere of powers that can be exercised without interference from the states.