What law did the US Supreme Court declare unconstitutional in Marbury v. Madison?

The Marbury v Madison (1803) decision concerned Article III of the Constitution, especially the section which states that "the judicial power shall extend to all cases . . . arising under the Constitution." The decision of Marbury v Madison resolved any doubt about that clause. The power of Judicial Review, the right to rule on the actions and acts of the federal government, rested with the federal courts. This decision gave the Supreme Court the power to declare laws unconstitutional.

Case Citation:

Marbury v. Madison, 5 US 137 (1803)