Citizenship is today considered to be the binding element of a national community and is an instrument and object of social closure. National citizenship draws boundaries between states. It is today one of the most powerful instruments of exclusion, every modern state identifies a particular set of persons as its citizens and defines all others as non-citizens, as aliens. At the same time, citizenship is an instrument of closure within states. A conceptual, legal, and ideological boundary between citizens and foreigners or migrants is established by every state. Every state discriminates between citizens and resident foreigners, reserving certain rights and benefits, as well as certain obligations, for citizens. Every state claims to be the state of, and for, a particular, bounded citizenry, usually conceived as a nation. In this sense, the modern nation-state is inherently nationalistic. Its legitimacy depends on its promoting the interests of a particular, bounded citizenry.2