The Louisiana Purchase

As Americans moved west of the Appalachians, the Mississippi River and the port of New Orleans became essential outlets for western farm produce. Spain had owned Louisiana since 1762, and the Pinckney Treaty of 1795 secured Americans’ right to navigate the river and ship goods through New Orleans. Then, in 1800, Spain secretly returned Louisiana to France. Napoleon Bonaparte planned to reconquer Saint-Domingue (Haiti) from the enslaved people who had overthrown slavery there, and to use Louisiana as the granary for a revived French empire in the Americas.

A powerful France at New Orleans alarmed Americans. Jefferson wrote that there was one spot on the globe whose possessor was “our natural and habitual enemy. It is New Orleans.” He sent James Monroe to join Robert Livingston in France to buy New Orleans and West Florida. Meanwhile the French army in Saint-Domingue was destroyed by yellow fever and fierce Haitian resistance, and war with Britain loomed again. Napoleon abandoned his American plans.

To the Americans’ surprise, France offered not just New Orleans but all of Louisiana. Far exceeding their instructions, Livingston and Monroe agreed to buy it for $15 million and signed the treaty on April 30, 1803. Jefferson, who had always insisted on a strict reading of the Constitution, found nothing in it authorizing the purchase of territory. He considered an amendment but, given public enthusiasm and the land’s value, set his scruples aside. The Senate ratified the treaty, and the United States took possession that December.

The treaty promised that the territory’s inhabitants would be incorporated into the Union and admitted to the rights of citizens. Jefferson sent the Lewis and Clark Expedition to explore the new lands. The purchase strengthened Jefferson’s popularity and weakened the Federalists, many of whom feared that new western states would reduce New England’s influence.

Louisiana was the first in a long series of territorial expansions that, within fifty years, carried the United States to the Pacific. Each expansion reopened the question of whether slavery would spread west, leading to the Missouri Compromise and the crises that ended in civil war. The purchase also ignored the people who actually lived on the land: thousands of Native Americans in dozens of nations, whose rights France could not sell and who would be pushed off much of it in the decades that followed. Jefferson’s decision helped establish the principle of the federal government’s implied powers.