Americans had assumed that they would someday buy or take New Orleans
from Spain, which did not have the military strength to resist the United States. In 1801, however, France, which could block America's westward expansion or close New Orleans, bought Louisiana from Spain. Jefferson sent a mission to France to buy New Orleans. Napoleon, for reasons of his own, offered to sell all of Louisiana, an area larger than the United States
at that time, for only $15 million.
C. The Lewis and Clark Expedition
Even before purchasing Louisiana, Jefferson sent an exploring party into the area (the Lewis and Clark Expedition). Their report on its economic prospects
reaffirmed Jefferson's desire that it belong to the United States. When he