The United States Senate Ratifies The Louisiana Purchase Treaty

On October 20, 1803, the Senate ratified the Louisiana Purchase Treaty by a vote of twenty-four to seven.

The agreement, which provided for the purchase of the western half of the Mississippi River basin from France at a price of $15 million, or approximately four cents per acre, doubled the size of the country and paved the way for westward expansion beyond the Mississippi.

Spain had controlled Louisiana and the strategic port of New Orleans with a relatively free hand since 1762. However, Spain signed the Treaty of San Ildefonso in 1800 under pressure from Napoleon Bonaparte, a secret agreement retroceding the territory of Louisiana to France.

News of the agreement eventually reached the U.S. government. President Thomas Jefferson feared that if Louisiana came under French control, American settlers living in the Mississippi River Valley would lose free access to the port of New Orleans. On April 18, 1802, Jefferson wrote a letter to Robert Livingston, the U.S. minister to France, warning that, "There is on the globe one single spot, the possessor of which is our natural and habitual enemy. It is New Orleans…"

Napoleon, faced with a shortage of cash, a recent military defeat in Santo Domingo (present-day Haiti), and the threat of a war with Great Britain, decided to cut his losses and abandon his plans for an empire in the New World. In 1803, he offered to sell the entire territory of Louisiana to the United States for $15 million.

The Louisiana Purchase (French: Vente de la Louisiane "Louisiana Sale") was the acquisition by the United States of America of 828,800 square miles (2,147,000 km2) of the French territory Louisiane in 1803. The U.S. paid 60 million francs ($11,250,000) plus cancellation of debts worth 18 million francs ($3,750,000), a total cost of 15 million dollars for the Louisiana territory.[1][2][3]

The Louisiana Purchase encompassed portions of 14 current U.S. states and 2 Canadian Provinces. The land purchased contained all of present-day Arkansas, Missouri, Iowa, Oklahoma, Kansas, Nebraska, parts of Minnesota that were west of the Mississippi River, most of North Dakota, nearly all of South Dakota, northeastern New Mexico, the portions of Montana, Wyoming, and Colorado east of the Continental Divide, and Louisiana west of the Mississippi River, including the city of New Orleans. (The Oklahoma Panhandle, and southwestern portions of Kansas and Louisiana were still claimed by Spain at the time of the Purchase.) In addition, the Purchase contained small portions of land that would eventually become part of the Canadian provinces of Alberta and Saskatchewan. The land included in the purchase comprises around 23% of the territory of the United States today.[2]

The purchase was a vital moment in the presidency of Thomas Jefferson. At the time, it faced domestic opposition as being possibly unconstitutional. Although he felt that the US Constitution did not contain any provisions for acquiring territory, Jefferson decided to purchase Louisiana because he felt uneasy about France and Spain having the power to block American trade access to the port of New Orleans.