Which case was the first in which the Supreme Court struck down a state law on constitutional grounds?

The case that marked the first instance in which the Supreme Court struck down a state law on constitutional grounds is Fletcher v. Peck. This decision, rendered in 1810, involved a dispute over land grants in Georgia. The Court held that the state of Georgia was not allowed to invalidate a land grant because it violated the Contract Clause of the Constitution, which protects contracts from being impaired by state legislation.

This case is significant because it established the principle that the Supreme Court has the authority to declare state laws unconstitutional, thereby reinforcing the supremacy of the federal Constitution over state legislation. The ruling also set a precedent for future cases involving contracts and property rights, indicating the court's role in ensuring the protection of individual rights against state encroachment.

The impact of Fletcher v. Peck was foundational in laying the groundwork for the principle of judicial review regarding state laws, affirming the judiciary's power to check state actions that conflict with federal constitutional provisions.