What was Chief Justice Marshall's decision in the case of Marbury vs. Madison?

In the case of Marbury v. Madison (1803), Chief Justice John Marshall ruled that William Marbury had a right to his commission but that the Supreme Court did not have the jurisdiction to issue a writ of mandamus to compel Secretary of State James Madison to deliver it. Marshall declared that the section of the Judiciary Act of 1789 that granted the Supreme Court the power to issue such writs was unconstitutional, establishing the principle of judicial review. This landmark decision affirmed the Court's authority to invalidate laws that conflict with the Constitution, solidifying the judiciary's role as a co-equal branch of government.