In this 55-page working paper from the Office of Population Research at Princeton, Marta Tienda examines the relationship between demography and the social contract in the United States, with a particular emphasis placed on historical and contemporary debates about the nature of immigration. As Professor Tienda states in her work, "immigration strains commitment to the democratic principles of inclusion and equity by redrawing the boundaries of membership based on ascription and an ever more narrow definition of citizenship." Throughout the work, Professor Tienda draws on diverse disciplinary traditions and demographic data in examining this complex subject. Given the recent debates and policy changes over the past few years, including numerous local initiatives to restrict voting to American citizens in certain states, Professor Tienda's scholarship offers an important sociological perspective on the subject at hand.