Citizenship can be defined as "the status of having the right to participate in and to be represented in politics." 1 It is a collection of rights and obligations that give individuals a formal juridical identity. T.H. Marshall, whose work has long dominated the debates about social citizenship, considered citizenship as "a status bestowed on those who are full members of a community. All who posses the status are equal with respect to the rights and duties with which the status is endowed."
Historically the demands for citizenship rights emerged in response to the growing power of the modern state. It is the product of the development of the modern state in the direction of unitary internal sovereignty. Originally, the demand for citizenship involved the enjoyment of legal and political rights, but early in the twentieth century citizenship was redefined to include social or welfare rights.
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
Although every country has its own laws regarding citizenship, there are two main categories into which these laws fall. In the first one, jus sanguinis, the principle of blood, descent and heritage play a pivotal role in defining who is, and can become, a citizen. Where people were born is not as important as if and how they can trace their ancestry back to the origin country. In this context, the term foreigner refers to those in the population whose heritage cannot be traced back to the host country. In general, under jus sanguinis citizenship policies, it is often difficult for foreigners to naturalise, even if they are long-term residents or were native born to the country. Those foreigners who do naturalise typically have to demonstrate that they meet the required integration criteria, such as language skills or knowledge of the country's culture and history.
The second principle, jus solis, defines citizens as those born within the country, regardless of the citizenship of the parents. Foreign-born residents can, under certain circumstances, change their status and become citizens through naturalisation. When combined, both place of birth and citizenship status can be used to divide the population into three categories, native-born citizens, foreign-born citizens, and non-citizens, and define who among the foreign born has acquired the full rights and responsibilities bestowed on all citizens.
Some states' citizenship law incorporates elements of both principles. The historical circumstances under which the principle of popular sovereignty became institutionalised in secular urban societies or in agrarian peasant societies explain the state's choice of which principle to base its citizenship on.
In several discussions over the last decades, issues of citizenship have been seen from the classical perspective of citizenship as the legal and political expression of nationality. A citizen has come to denote "a national with voting and passport rights". This has sometimes had the effect of reducing questions concerning citizenship to their legal minimum, i.e. matters of nationality. At the same time, migration and intermarriage undermine the traditional one-person/one state situation, so that many people are born with dual citizenship now. Though some states have suppressed the possibility of dual citizenship, citizenship laws in general are often being relaxed or disregarded.
1 Baylis, J & Smith, S. 2001. The Globalisation of World Politics. An introduction to international relations. Oxford University Press.
2 Brubaker, R. 1992. Citizenship and Nationhood in France and Germany. (EUA): Harvard University Press.