The Louisiana Godsend and The Empire of Liberty (2:59) 

Jefferson  asked for $2 million to buy the port - requested money in case we had to go to war over the river and/or the port gave– Robert Livingston and James Monroe – permission to ask France to sell us the port for $2 million

Napoleon

had hopes of regaining control of some land in the western hemisphere fighting against Toussaint L’Ouverture in the West Indies France lost because of a combination of yellow fever and slow reinforcements. The Louisiana Purchase was finalized on April 30, 1803.

Jefferson had a dilemma, since the Constitution said nothing about purchasing foreign land, but on the other hand, this deal was simply too good to pass up!

 After considering an amendment, Jefferson finally decided to go through with the deal anyway, even though nothing in the Constitution talked about land purchases. Jefferson had been a strict interpreter of the Constitution, but he was now using a loose interpretation.

Federalists, normally loose interpreters, took a strict interpretation and opposed the purchase. Federalist didn’t want the new lands because they correctly foresaw new lands meant new settlers and new states, which meant more farmers and more Republicans.

Thus, both parties made a full 180° turnaround from their previous philosophical beliefs about the Constitution simply because of the practical matters at hand.

The Senate quickly approved the purchase with Jefferson’s urging, and the Louisiana Purchase doubled the size of the United States. This was the biggest bargain in history averaging 3 cents per acre. The purchase created a precedent of acquisition of foreign territory through purchase.