April 30, 1803 – The Louisiana Purchase Treaty Doubles the Size of the U.S.

On this date in history, what is called the greatest real estate deal in history was formalized by the signing of the Louisiana Purchase Treaty. For the price of $15 million, or approximately four cents an acre, the U.S. acquired some 827,000 square miles of land west of the Mississippi River, a deal which doubled the size of the United States, and opened up the continent to westward expansion.

Robert Livingston and James Monroe had traveled to France to negotiate the purchase only of New Orleans and its environs, for which they were prepared to pay up to $10 million. They were astounded when they found that the whole territory could be had for $15 million (which included the forgiveness of France’s $3.75 million debt to America). As an article in Mental Floss explains,

France needed another lucrative funding source for Napoleon’s ambitions. The emperor turned his attention to selling the Louisiana Territory — an enormous chunk of North America, the western watershed of the Mississippi River, that Spain had relinquished to France in 1800 in the secret Third Treaty of San Ildefonso. Napoleon didn’t have the military power to patrol this vast territory, and once France lost its Caribbean colonies, the North American land became a boondoggle.”

Although the two diplomats had no way to communicate with President Thomas Jefferson, they were certain he would see the wisdom of taking up the offer.

On Saturday, April 30, 1803, the Louisiana Purchase Treaty was signed by Robert Livingston, James Monroe, and Barbé Marbois in Paris. Jefferson announced the treaty to the American people on July 4. There was widespread opposition to it; the move was regarded as not strictly constitutional, a problem of which Jefferson was well aware.

(Jefferson rationalized the action in a letter to John Breckinridge, United States Attorney General during Jefferson’s second term, writing: “It is the case of a guardian, investing the money of his ward in purchasing an important adjacent territory; and saying to him when of age, I did this for your good.”)

The House called for a vote to deny the request for the purchase, but it failed by two votes, 59–57.

The United States Senate ratified the treaty with a vote of twenty-four to seven on October 20. On the following day, the Senate authorized President Jefferson to take possession of the territory and establish a temporary military government. Mental Floss points out:

The actual geographic limits weren’t agreed upon until almost 20 years later, when the Convention of 1818 and the Adams-Onís Treaty of 1819 established the boundaries.”