Darwin's notion of struggle for survival was quickly appropriated by the racists once the Social Darwinist raised the struggle from the biological to the social plane. Such a struggle, legitimized by the latest scientific views, justified the racists' conceptions of superior and inferior peoples and nations and validated the conflict between them. The racists' appropriation of these scientific categories won for racist thought a much wider circulation than its ideas warranted. What satisfaction there must have been to find that one's prejudices were actually expressions of scientific truth. What greater authority than science could the racists have invoked? A populace astounded by the changes in its physical and social environment already attributed most of these changes to science and technology. The addition of a racial science seemed no more than logical. Not all Social Darwinists were anti-Semites or even racists in any specific sense, any more than all anti-Semites were Social Darwinists, but the development of Social Darwinism gave to racism and anti-Semitism and the völkisch movement a foundation it would not have found for itself.
Karl A. Schleunes, The Twisted Road to Auschwitz: Nazi Policy toward German Jews, 1933-39, pp. 31-2