The Louisiana Purchase: Jefferson’s constitutional gamble. On October 20, 1803, the Senate ratified a treaty with France, promoted by President Thomas Jefferson, that doubled the size of the United States. The Louisiana Purchase was a seminal moment for a new nation.Click to see full answer. Keeping this in consideration, why did Jefferson make the Louisiana Purchase?The Louisiana Purchase was a land purchase made by United States president, Thomas Jefferson, in 1803. He bought the Louisiana territory from France, which was being led by Napoleon Bonaparte at the time, for 15,000,000 USD. Napoleon Bonaparte sold the land because he needed money for the Great French War.Additionally, was Jefferson right to make the Louisiana Purchase? An amendment of the Constitution seems necessary for this.” Jefferson drafted an amendment that would authorize the purchase of Louisiana retroactively. But Jefferson’s cabinet members argued against the need for an amendment, and Congress disregarded his draft. The Senate ratified the treaty in October of 1803. Similarly, it is asked, how did Jefferson feel about the Louisiana Purchase? Although the purchase was thought of by some as unjust and unconstitutional, Jefferson determined that his constitutional power to negotiate treaties allowed the purchase of what became fifteen states. In hindsight, the Louisiana Purchase could be considered one of his greatest contributions to the United States.Why was the Louisiana Purchase considered unconstitutional?Because land purchase treaties were permitted by the Constitution, and because the Louisiana Purchase was a land treaty that received the consent of the Senate, it seems evident that the Louisiana acquisition was wholly constitutional.