In many democratic countries immigrants obtain voting rights only after several years. This paper provides an explanation for this phenomenon in the framework of a, dynamic migration model of two countries (North-South). In this framework individuals differ in their preferences regarding the supply of a public good, or more generally, regarding some public policy issue. The individual migration decision takes into account both the pecuniary opportunities and the supplies of the public good — which are determined by majority vote in the respective countries. Everyone has been an immigrant at some time in the past. In equilibrium, however, there is an intrinsic political conflict between residents of different "vintages," which implies that longer-time residents are better off postponing the granting of voting rights to more recent immigrants.