What key principle did Marbury v. Madison establish?

• A. Judicial review—the courts can strike down laws that violate the Constitution.
• B. Separation of church and state.
• C. Federal supremacy.
• D. Free speech protections.

Answer: (A)

At its core, this question tests judicial review—the idea that the courts have the final say on whether laws or government actions conform to the Constitution. In Marbury v. Madison, the Supreme Court asserted that the Constitution is the supreme law of the land and gave the judiciary the authority to interpret it and strike down any statute or action that violates it. This creates a crucial check on both Congress and the President, ensuring that constitutional rights and powers are protected through a final, authoritative interpretation. The other topics—church-state separation, federal supremacy, and free speech protections—are addressed in different contexts and were not the principle established by this case.