Cohens v. Virginia

Cohen v. Virginia (1821) was a Supreme Court case that clarified the relationship between state and federal courts. The case involved a dispute over a Virginia law trying to control conduct that had taken place partly outside Virginia's borders. The Court ruled that federal courts have the authority to review and overrule state court decisions if they violate federal laws or the U.S. Constitution. This case established the principle that federal law is supreme and ensures a uniform interpretation of constitutional rights across all states, reinforcing the power of federal courts to serve as a check on state actions.