Final answer:
The Supreme Court first applied the Supremacy Clause in McCulloch v. Maryland (1819), which established federal laws' supremacy over state laws when in conflict.
Step-by-step explanation:
The seminal case that firmly anchored its decision in the Constitution's Supremacy Clause was McCulloch v. Maryland in 1819, marking a pivotal moment in constitutional law. This landmark ruling laid the foundation for the doctrine of implied powers and unequivocally affirmed the supremacy of federal laws over state laws in the event of a conflict.
In McCulloch v. Maryland, the Supreme Court decisively established that the Constitution's Supremacy Clause, found in Article VI, renders federal laws and the Constitution itself the paramount legal authority. The case centered on Maryland's attempt to tax the Bank of the United States, and the Supreme Court declared this state-imposed tax unconstitutional. The crux of the ruling was that such taxation violated the principle of national supremacy embedded in the Supremacy Clause.
The doctrine of implied powers, crystallized through this decision, emphasized that the federal government possesses powers not explicitly outlined in the Constitution but necessary for carrying out its enumerated powers. McCulloch v. Maryland underscored the enduring authority of federal law and the Constitution, providing a foundational precedent for resolving conflicts between federal and state laws based on the clear mandate of the Supremacy Clause.