Louisianna Purchase, 1804

Thomas Jefferson made one of the most famous land purchases ever on this day in 1804.  While the Americans had a more or less solid hold on the eastern seaboard, the central swath of the country, with the mighty (and navigable) Mississippi River and a large part of the Missouri River within the territory, was up for grabs.  The Spanish held it at one point and so did the French.  Napoleon was hoping to make a big comeback in the Caribbean, and by virtue of French presence there, to resurge in the New World.

Let's just say things did not go their way.  Jefferson sent James Monroe to join Robert Livingston in France to try to purchase New Orleans and West Florida for as much as $10 million. Failing that, they were to attempt to create a military alliance with England. Meanwhile, the French Army in St. Domingue was being decimated by yellow fever, and war between France and England still threatened. Napoleon decided to give up his plans for Louisiana, and offered a surprised Monroe and Livingston the entire territory of Louisiana for $15 million. Although this far exceeded their instructions from President Jefferson, they agreed.

When news of the sale reached the United States, the West was elated. President Jefferson, however, was in a quandary. He had always advocated strict adherence to the letter of the Constitution, yet there was no provision empowering him to purchase territory. Given the public support for the purchase and the obvious value of Louisiana to the future growth of the United States, however, Jefferson decided to ignore the legalistic interpretation of the Constitution and forgo the passage of a Constitutional amendment to validate the purchase. This decision contributed to the principle of implied powers of the federal government.