Answer:
It was as President of the United States that Thomas Jefferson had the greatest impact on the Indian nations of North America. He pursued an Indian policy that had two main ends. First, Jefferson wanted to guarantee the security of the United States and so sought to bind Indian nations to the United States through treaties. The aim of these treaties was to acquire land and facilitate trade, but most importantly to keep them allied with the United States and not with European powers, namely England in Canada and Spain in the regions of Florida, the Gulf Coast and lands west of the Mississippi River. Secondly, Jefferson used the networks created by the treaties to further the program of gradual "civilization." His Federalists predecessors had begun this program, but it was completely in keeping with Jefferson's Enlightenment thinking. Through treaties and commerce, Jefferson hoped to continue to get Native Americans to adopt European agricultural practices, shift to a sedentary way of life, and free up hunting grounds for further white settlement.
https://www.commonlit.org/texts/excerpts-from-thomas-jefferson-s-writings-on-american-indians. The second paragraph of this link is the correct answer :).
