The Election of 1800 resulted in Jefferson and Burr receiving the same number of electoral votes, requiring the House of Representatives to break the tie. This led to the 12th amendment being passed, requiring separate electoral votes for president and vice president. In Marbury v. Madison, the Supreme Court established the principle of judicial review, allowing it to declare laws unconstitutional. The Louisiana Purchase doubled the size of the U.S. when President Jefferson bought land west of the Mississippi River to the Rocky Mountains from Napoleon Bonaparte of France for $15 million in 1803.