In the wake of the bitter 1800 election, outgoing President John Adams's 'midnight judges' commissions were left undelivered when Thomas Jefferson took office. William Marbury sued Secretary of State James Madison to force delivery, invoking a section of the Judiciary Act of 1789 that gave the Supreme Court original jurisdiction over such writs of mandamus. Chief Justice John Marshall's opinion is a masterclass in strategic restraint. He held that Marbury had a right to his commission and that the law provided a remedy — but that the Court itself could not grant that remedy, because the statute purporting to confer original jurisdiction impermissibly enlarged the Court's jurisdiction beyond what Article III allowed. Because a statute contrary to the Constitution cannot govern, Marshall declared, 'It is emphatically the province and duty of the judicial department to say what the law is.' That single sentence established judicial review: the Supreme Court's authority to invalidate acts of Congress that conflict with the Constitution. Every subsequent constitutional decision — from Brown v. Board to Dobbs — rests on Marbury's foundation. Its genius was avoiding a confrontation the young Court could not have won while cementing a power the Constitution had only implied.