Why did the Sioux resist signing any deals with the American government?

There were many reasons that the Sioux resisted. They didn't trust the American government. Broken promises and broken treaties from the government were now normal. The Sioux were also asked to change their lives and identities. The Sioux were nomadic people, the American government demanded assimilation into white culture. The Sioux were expected to stay in one place, farm, go to church.....Treaties were meant to strip the Sioux of their inherent land rights and their culture.