In response, Jefferson sent future U.S. president James Monroe to Paris to aid Livingston in the New Orleans purchase talks. In mid-April 1803, shortly before Monroe's arrival, the French asked a surprised Livingston if the United States was interested in purchasing all of Louisiana Territory.
Spain had not yet completed the transfer of Louisiana to France, and war between France and the UK was imminent. Out of anger towards Spain and the unique opportunity to sell something that was useless and not truly his yet, Napoleon decided to sell the entire territory.
The Louisiana Purchase was the latter, a treaty. The Constitution specifically grants the president the power to negotiate treaties which is just what Jefferson did. It is true that the Constitution does not specifically authorize Congress, let alone the executive branch, to purchase land from other nations.
In other words, it was the French who controlled the LA territory in 1763 until it was sold and the US had control over it.
Hoped this helped,
-Anime
(if it is incorrect, then I am sorry)
