Marbury v. Madison established the principle of judicial review that allows the Supreme Court to declare laws unconstitutional. The case was brought before the court after William Marbury sued James Madison for failing to deliver his judicial commission. The Supreme Court ruled that while Marbury was entitled to his commission, the court did not have the power to force Madison to deliver it as the section of the Judiciary Act of 1789 that allowed it was unconstitutional. Chief Justice John Marshall's reasoning was that if a law conflicts with the Constitution, which is the supreme law, then courts must uphold the Constitution.