The Policy of Assimilation was based on the idea that if Native Americans did not assimilate into white culture as the United States expanded, they would eventually die out. The policy was the source for many conflicts between the U.S. government and native tribes during the first half of the 19th century.
As the nation expanded, the government decided that it needed to regulate the trade activity of Native American tribes and their interaction with white settlers. The U.S. government also created a special bureau to monitor and negotiate between Native Americans and white settlers in the event of disputes. Native Americans, however, did not see themselves as part of the newly formed United States. They viewed themselves as sovereign nations that were not subject to governmental control.
As the Native Americans continued to resist government efforts to assimilate them, the U.S. government altered its position on assimilation and instead began pressuring tribes into signing treaties, in which they would voluntarily give up their lands east of the Mississippi and move west. Later, further legislation was passed that ended the U.S. government's attempts to relocate entire tribes. Instead, the government focused on relocating individual Native American's with their own property, in the hope that this would eventually lead to assimilation.