Which case solidified the Supreme Court's authority over state legislation concerning federal laws?

The case that solidified the Supreme Court's authority over state legislation concerning federal laws is McCulloch v. Maryland. This landmark decision, delivered in 1819, established two key principles: the supremacy of federal laws over state laws and the implied powers of Congress.

In McCulloch v. Maryland, the Supreme Court addressed whether the state of Maryland had the power to tax a federal bank (the Second Bank of the United States). Chief Justice John Marshall ruled that the federal government had the authority to establish a national bank under the Necessary and Proper Clause of the Constitution, which allowed for implied powers. The ruling emphasized that state actions could not interfere with valid constitutional exercises of power by the federal government, thereby reinforcing the notion that federal law takes precedence over state law.

This case is significant because it set a precedent for a strong interpretation of federal authority, affirming that the Supreme Court has the final say in disputes where federal and state laws conflict. This principle continues to be a cornerstone of federalism in the United States.