From Thomas Jefferson Encyclopedia
The Louisiana Purchase (1803) was a land deal between the United States and France, which gave the U.S. about 827,000 square miles of land west of the Mississippi River for $15 million dollars.
"This little event, of France's possessing herself of Louisiana . is the embryo of a tornado which will burst on the countries on both sides of the Atlantic and involve in it's effects their highest destinies."
President Thomas Jefferson wrote this prediction in an April 1802 letter to Pierre Samuel du Pont amid reports that Spain would retrocede to France the vast territory of Louisiana. As the United States had expanded westward, navigation of the Mississippi River and access to the port of New Orleans had become critical to American commerce, so this transfer of authority was cause for concern. Within a week of his letter to du Pont, Jefferson wrote U.S. Minister to France Robert Livingston: "Every eye in the U.S. is now fixed on this affair of Louisiana. Perhaps nothing since the revolutionary war has produced more uneasy sensations through the body of the nation."
The presence of Spain was not so provocative. A conflict over navigation of the Mississippi had been resolved in 1795 with a treaty in which Spain recognized the United States' right to use the river and to deposit goods in New Orleans for transfer to oceangoing vessels. In his letter to Livingston, Jefferson wrote, "Spain might have retained [New Orleans] quietly for years. Her pacific dispositions, her feeble state, would induce her to increase our facilities there, so that her possession of the place would be hardly felt by us." He went on to speculate that "it would not perhaps be very long before some circumstance might arise which might make the cession of it to us the price of something of more worth to her."
Jefferson's vision of obtaining territory from Spain was altered by the prospect of having the much more powerful France of Napoleon Bonaparte as a next-door neighbor.
France had surrendered its North American possessions at the end of the French and Indian War. New Orleans and Louisiana west of the Mississippi were transferred to Spain in 1762, and French territories east of the Mississippi, including Canada, were ceded to Britain the next year. But Napoleon, who took power in 1799, aimed to restore France's presence on the continent.
The Louisiana situation reached a crisis point in October 1802 when Spain's King Charles IV signed a decree transferring the territory to France and the Spanish agent in New Orleans, acting on orders from the Spanish court, revoked Americans' access to the port's warehouses. These moves prompted outrage in the United States.
While Jefferson and Secretary of State James Madison worked to resolve the issue through diplomatic channels, some factions in the West and the opposition Federalist Party called for war and advocated secession by the western territories in order to seize control of the lower Mississippi and New Orleans.
Aware of the need for action more visible than diplomatic maneuverings and concerned with the threat of disunion, Jefferson in January 1803 recommended that James Monroe join Livingston in Paris as minister extraordinary. (Later that same month, Jefferson asked Congress to fund an expedition that would cross the Louisiana territory, regardless of who controlled it, and proceed on to the Pacific. This would turn out to be the Lewis and Clark Expedition.) Monroe was a close personal friend and political ally of Jefferson's, but he also owned land in Kentucky and had spoken openly for the rights of the western territories.
Jefferson urged Monroe to accept the posting, saying he possessed "the unlimited confidence of the administration and of the western people." Jefferson added: "All eyes, all hopes, are now fixed on you . for on the event of this mission depends the future destinies of this republic."
Shortly thereafter, Jefferson wrote to Kentucky's governor, James Garrard, to inform him of Monroe's appointment and to assure him that Monroe was empowered to enter into "arrangements that may effectually secure our rights & interest in the Mississippi, and in the country eastward of that."