In 1803's Marbury v. Madison, the Supreme Court articulated for the first time the doctrine of judicial review.
With the doctrine of judicial review, the Supreme Court now had a tool to make themselves a co-equal branch with the legislative and executive branch in that it enabled it to review the actions of the legislative and executive branch to determine whether or not they acted appropriately in regards to the Constitution.
The ruling gave the judiciary a way to declare the acts of Congress unconstitutional thus establishing the doctrine of judicial review.
Marbury v. Madison legal case of 1803 was the first Supreme Court decision where an act of Congress was declared unconstitutional.
James Madison failed to finalize the former president's appointment of William Marbury as Justice of the Peace. Marbury petitioned the Supreme Court for a remedy of his situation but was denied it. The Court said that although he was entitled to a remedy, expending the Supreme Court's original jurisdiction was unconstitutional.
