On the other hand, Jefferson had some reservations about the constitutionality of the purchase. He believed that the federal government did not have the authority to acquire new territory without the explicit consent of the states. However, he ultimately decided that the benefits of the purchase outweighed the constitutional concerns.
In a letter to Robert R. Livingston, the American ambassador to France who had negotiated the purchase, Jefferson wrote: "The treaty which you have sent me is viewed here as a masterpiece of diplomacy, and of a foresight and judgment superior to any example in the history of diplomacy... Nothing since the Roman acquisition of Sicily, can in any degree compare with it."
Jefferson also recognized the potential for the Louisiana Territory to become a source of conflict between the United States and the various Native American tribes that inhabited the region. He believed that it was essential to establish good relations with these tribes and to ensure that their rights were respected.
Overall, Jefferson's reaction to the Louisiana Purchase was one of excitement, gratitude, and cautious optimism. He saw the purchase as a major milestone in the history of the United States and as an opportunity to shape the future of the nation.