Answer:
Since Indian tribes living there appeared to be the main obstacle to westward expansion, white settlers petitioned the federal government to remove them. ... Under this kind of pressure, Native American tribes—specifically the Creek, Cherokee, Chickasaw, and Choctaw—realized that they could not defeat the Americans in war.
Step-by-step explanation:
In simpler terms, the Native American tribes did not want to give up their land and America wanted to keep expanding ultimately into Native American land.