This commentary originally aired on October 20, 2015. The United States Congress ratified the Louisiana Purchase Treaty on October 20th, 1803, officially transferring 826,000 square miles of land from French to American ownership for $15 million. It’s considered one of the greatest real estate deals in history. But at the time, purchasing the land between the Mississippi River and the Rocky Mountains presented constitutional and political questions for the United States. Constitutionally,