Final answer:
Thomas Jefferson had a hard time buying the Louisiana Territory due to constitutional limitations, but he believed it was necessary for westward expansion and an agrarian society. He assigned negotiators Robert Livingston and James Monroe. Napoleon was willing to sell because his vision for Louisiana had failed.
Step-by-step explanation:
Thomas Jefferson had a hard time buying the Louisiana Territory because it was not specified in the Constitution that the president had the power to make such a purchase. Jefferson was strict about adhering to the Constitution, but he believed that acquiring the territory was necessary for the country's westward expansion and the dream of an agrarian society.
Jefferson assigned Robert Livingston and James Monroe to negotiate the purchase, and Napoleon, the seller, was motivated to sell because of the failure of his vision for Louisiana. The United States eventually bought the territory for $15 million, doubling its size.