Which decision established Judicial Review?

• A. Marbury v. Madison
• B. McCulloch v. Maryland
• C. Korematsu v. United States
• D. United States v. Nixon

Answer: (A)

Judicial review is the power of the courts to declare laws or government actions unconstitutional, keeping the Constitution as the supreme law. Marbury v. Madison established that power for the courts, holding that a portion of the Judiciary Act of 1789 could not be enforced because it extended the Supreme Court beyond what the Constitution allowed. By asserting this authority, the Court created the mechanism by which laws and executive actions can be checked against the Constitution. The other options involve important constitutional issues—federal power over states (McCulloch v. Maryland), civil liberties during war (Korematsu v. United States), and presidential accountability under the law (United States v. Nixon)—but none set the principle of judicial review. Thus, the decision that established judicial review is Marbury v. Madison.