How were american indians were under siege by 1820?

The Natives figured they could deal with the Europeans, yet they were excessively behind. First, in the manner, they battle, at that point, nourishment admission, drug, etc. The Natives were getting more fragile, and the Europeans continued trampling them. The Natives lost the opportunity. In the content, it says, "By 1820 they had lost control of land east of the Mississippi River, and an insignificant sixty years after the fact the relatives of those newcomers roosted so unstably on the Atlantic in 1620 ruled the landmass right to the Pacific.