The destruction of the indigenous people of modern day North America had much to do with the implementation of the policy of ethnic cleansing. Ethnic cleansing is the systematic forced removal of ethnic or religious groups from a given territory with the intent of making it ethnically or religiously homogeneous. The forces applied may be various forms of forced migration (deportation, population transfer), as well as mass murder, and intimidation. Ethnic cleansing was a sudden process but one that ebbed and flowed throughout the four-hundred-year period of contact between Europeans, Americans, and the indigenous people. Europeans and Americans considered this policy to be just and righteous.