Ian F. Haney López, White By Law: The Legal Construction of Race (New York: New York University Press, 1996), 122ff.
Irrespective of the use of violence, however, it may seem that at this coercive level laws construct races only at the margins. Granting that races are social constructions, some may suggest that legal rules patrol only the borders between races, resolving just those rare cases not already clearly defined within the underlying social systems of racial division. Arguably, only the person not clearly White or Black has her race determined in a prerequisite case or by her neighborhood. However, a focus on the coercive aspect of law seems to explain more than just the legal construction of race at the margins. Certainly the prerequisite cases legally established the legal identity of groups we now regard as firmly at the core of racial categories, for example the Japanese, and Jim Crow laws were indispensable in maintaining and even extending the social differentiation established through the slave codes and threatened during Reconstruction. Nevertheless, the explanatory power of this model should be questioned. How does law-as-coercion explain the continuing significance of race in a  postsegregation era? If races have been created through coercion, why hasn’t the end to the legal enforcement of racial differences been followed by a collapse in racial systems? Or, what can such a model tell us about the prevalent belief that races are legally fashioned? If races have been imposed, why is it that the vast majority of people embrace race so willingly? And why do these same people so vigorously deny that they have been coerced into a racial identity? Races are much more deeply embedded in our society than a theory of law-as-coercion would seem to explain. If law is a full participant in the construction of races, it must fashion races through some additional mechanism besides simple direct behavioral control.