The landmark case that established the principle of "judicial review" is Marbury v. Madison, decided in 1803 by the U.S. Supreme Court. This case arose when William Marbury sued Secretary of State James Madison to compel him to deliver a commission. Chief Justice John Marshall ruled that while Marbury had a right to his commission, the court did not have the jurisdiction to issue a writ of mandamus because the section of the Judiciary Act of 1789 that granted such power was unconstitutional. This decision established the Supreme Court's authority to review and invalidate legislation that conflicted with the Constitution, solidifying its role as a co-equal branch of government.