President Jefferson endorsed the purchase but believed that the Constitution did not provide the national government with the authority to make land acquisitions. He pondered whether a constitutional amendment might be needed to legalize the purchase. After consultations Jefferson concluded that the president's authority to make treaties could be used to justify the agreement. Therefore, the Louisiana Purchase was designated a treaty and submitted to the Senate for ratification. The Senate ratified the treaty October 20, 1803, and the United States took possession of the territory December 20, 1803.
A proprietary colony was granted to an individual or group by the British rulers and were granted full rights of self-government. For example, Pennsylvania was a proprietary colony.