In Marbury v. Madison (1803) the Supreme Court announced for the first time the principle that a court may declare an act of Congress void if it is inconsistent with the Constitution. William Marbury was appointed a justice of the peace for the District of Columbia in the final hours of the Adams administration. James Madison, Thomas Jefferson’s secretary of state, refused to deliver Marbury’s commission. Marbury and three others petitioned for a writ of mandamus to force delivery of the commissions.
Chief Justice John Marshall, writing for a unanimous Court, denied the petition and refused to issue the writ. He found that the petitioners were entitled to their commissions, yet he held that the Constitution did not give the Supreme Court the power to issue writs of mandamus. The Judiciary Act of 1789 allowed such writs to be issued, but the act was inconsistent with the Constitution and therefore invalid.
The immediate effect of the decision was to deny power to the Court. However, its long-term effect has been to increase the Court’s power through judicial review. The rule established that ‘it is emphatically the province and duty of the judicial department to say what the law is.’ As a result of Marbury v. Madison, the Supreme Court has been the final judge of the constitutionality of congressional legislation.
Source: Marbury v. Madison
U.S. National Archives & Records Administration