Further, it is difficult to know what might be meant by any Native American "racial" identity. Race is a disputed term, but is often said to be a social (or political) rather than biological construct. The issue of Native American racial identity was discussed by Steve Russell (2002, p68), "American Indians have always had the theoretical option of removing themselves from a tribal community and becoming legally white. American law has made it easy for Indians to disappear because that disappearance has always been necessary to the 'Manifest Destiny' that the United States span the continent that was, after all, occupied." Russell contrasts this with the reminder that Native Americans are "members of communities before members of a race."