Napoleon I’s decision to cede the Louisiana territory to the United States in 1803 was a boon for the fledging American republic. The purchase of approximately 830,000 square miles of the trans-Mississippi west doubled the size of the United States and facilitated its expansion westward.
France had been in possession of the territory since its exploration by La Salle in 1682, but ceded it to Spain at the end of the Seven Years’ War. Under Spanish rule, citizens of the United States living in the trans-Appalachian West were allowed free use of the Mississippi River and access to the port of New Orleans for transshipment of their goods to oceangoing vessels.
Expansionist-minded Americans accepted this arrangement because they were confident that America’s growing population would eventually end the nominal rule of Spain in Louisiana.
The situation changed drastically when Spain ceded Louisiana to France by a secret treaty in 1800 that was reaffirmed in 1801. It was widely assumed that Napoleon planned to use Louisiana for the establishment of an empire in the Americas and that he would negate America’s right of deposit at New Orleans.
For President Thomas Jefferson, “this affair of Louisiana” was troublesome. He was faced with the possibility of a French barrier to American expansion, the militancy of western Americans who chafed at the news of the cession, and personal attacks by members of the Federalist Party.
Jefferson decided on a pragmatic approach to the situation. He reinforced American security in the West and coupled it with shrewd diplomacy. Via his French friend Pierre Samuel du Pont de Nemours, he sent an open letter to the American minister in France, Robert R. Livingston.
Jefferson hinted at the possibility of an alliance between the United States and England. He also instructed Livingston to negotiate for the purchase of the port of New Orleans and dispatched James Monroe to Paris to help.
By the time Monroe arrived in Paris on April 12, 1803, Napoleon’s fortunes had changed. His plans for a New World empire were foiled by the inability of his troops to quell an uprising in Saint-Domingue, and he was faced with an impending war with England. Talleyrand, the French foreign minister, informed the Americans that France was willing to sell all Louisiana.
The Americans, without presidential authorization, accepted Talleyrand’s offer and signed the Louisiana Purchase Treaty on May 2, 1803. The negotiated price was $15,000,000 of which $3,750,000 was used to settle the claims of American citizens against France.
Upon receipt of the treaty, Jefferson hesitated. Preferring a constitutional amendment that would sanction territorial acquisition, but faced with a favorable fait accompli, Jefferson set aside his narrow constructionist view of the Constitution and accepted the treaty. The Senate ratified the Louisiana Purchase Treaty on October 20, 1803.