Thomas Jefferson wanted USA to expand its borders without war and acclimatize the natives with Western Culture.
Explanation:
Jefferson was a proponent of the belief that the natives should be forced to give up their own customs and language in favor of English and western culture.
For this, they must live with the people of USA, even if in segregation with heavily dictated lives.
Jefferson wanted to expand the borders of USA but without a war with the Natives. Instead he wanted this slow process to do the job instead.
