Following Emile Durkheim, T. H. Marshall and Talcott Parsons developed a na
tional model of citizenship which rests on the assumption that social order
can be guaranteed by progressive inclusion of all members of society into
an ever greater set of citizenship rights. However, in the face of massive
postwar-immigration into western liberal democracies citizenship turns out
to be a powerful instrument of social closure. The article argues that unde
r conditions of ethnic heterogeneity the nation state achieves social order
by an extensive exclusion of migrants from citizenship rights. From the pe
rspective of the theory of social closure the conflicts between the nation-
state and immigrants for inclusion into citizenship rights can be understoo
d as struggles for belonging. The case of Germany demonstrates how citizens
hip operates as a mode of social closure.