Indian removal had been taking place in the United States since the 18th Century as more Americans made the move westward. In the early 19th Century, Andrew Jackson and the majority of white Americans like him, wanted the Indians to move west of the Mississippi, out of the way from white expansion. Popular thought was that the Indians were savages who could not be civilized, and integration with the white culture was not a possibility.
Through the next several years, Indian tribes all over the eastern front were forced to reservations of proportional inequality compared with land once owned. The United States bought the land from the Indians while using its brute power to force unruly tribes west. No matter how much they tried, the Indians were no match for the strength of the United States.
Indians of the Sauk and Fox tribes tried to take back land that was ceded to the United States wrongfully. When they inhabited the vacant land, Americans saw them as a threat to the white settlements close-by. Illinois state militia was sent in to destroy the so-called "invaders." The Indians retreated back and the militia continued to attack until most had been killed.
Were Americans justified in the mass movement of Indian tribes? I would have to say they were not. I cannot see the logic in their assumptions of the Indians. For the most part, little interaction took place with the Indians. Yet, Americans still believed they were uncivilized.
Perhaps the problem was in terms of envy. Indians had been capable of adapting to land and using the land efficiently for years at a time. I think Americans saw how the Indians were able to do this, and became jealous of their superior farming abilities. Land was becoming useless in the east, and Indians had been able to use their land repeatedly. Americans saw this fertile land as rich in potential profit and were willing to go to any length in acquiring it.
Evidence of the two cultures working together in a society was apparent in New Mexico, Texas, and California. If these people were able to survive and live off each other, I would have to assume that had the United States made an effort, they could have resolved this situation in an easier manner. Unless it was jealousy that was driving them to take the Indian land. Something tells me it was exactly that which caused such a debacle. Superior in farming techniques and land use, the Indians efficient ways were the downfall of their land availability.