A citizen is a member of a political community who enjoys the rights and assumes duties of membership. This broad definition is evident as illustrated in the works of contemporary authors as well as in the d’Alembert’s Encyclopédie  of the reputable French philosopher .
The Encyclopédie defines the citizen as ‘a member of a free society of many families, who shares in the rights of this society and enjoys its immunities’. In the 18th century, the main preoccupation for a person living in a monarchy was the relationship between the concepts of ‘citizen’ and ‘subject’. Effectively, two main philosophical principles had been conceptualised which consider whether the above concepts the same in principle (Hobbes) or different (Aristotle).
Aristotle claimed, “if a central element of citizenship consisted of participating in the business of ruling, the consequence was that citizenship is impossible in a monarchy, as an individual can only be a ‘subject’ in this case”. Against this dangerous idea, Hobbes had argued that: “Whether a Common-wealth be Monarchical, or Popular, the freedom is still the same” (Hobbes 1991, 149). He further mentions that whether we live in a monarchy or a republic, our obligation to obey the law is the same. This is a distinctive approach to citizenship and this philosophical principle is still practised in the 21st century. This does not mean that the concepts have become controversial over time. After a long period of relative calm, there has been a dramatic upsurge in philosophical interest in citizenship since the early 1990s. Two broad challenges have led theorists to re-examine these concepts: first, the need to acknowledge the internal diversity of modern liberal democracies and second, the pressures formed by globalisation on the sovereign state.
Dimensions of Citizenship
The modern concept of citizenship is considered in three main elements or dimensions (Cohen 1999; Kymlicka and Norman 2000; Carens 2000). The first dimension is citizenship as legal status which is defined by civil, political and social rights. The second considers citizens specifically as political agents, actively participating in a society’s political institutions. The third refers to citizenship as membership in a political community that gives a distinct source of identity. This is physically demonstrated though the use of diplomatic passports and ordinary passports depending on the political status of the individual.
Relations between the three dimensions are complex, the rights a citizen enjoys will partly be defined by the range of available political activities (Rawls 1972, 544). A strong community identity can motivate citizens to participate actively in their society’s political life. This means that both considerations work ‘hand in hand’ and will affect the overall strength of citizenship based on political participation and unity in society.
Models of Citizenship
Considerations about citizenship usually have one of two models: the republican or the liberal. The republican model’s sources can be found in the writings of authors like Aristotle, Tacitus, Cicero, Machiavelli, Harrington and Rousseau, and in distinct historical experiences: from Athenian democracy and Republican Rome to the Italian city-states and workers’ councils. The liberal model’s origins are traceable to the Roman Empire and early-modern reflections on Roman law (Walzer 1989, 211). The two models, at first instance, present us with a clear set of alternatives, the citizen appears either as the primary political agent, as illustrated in the republican model, or liberal, where an individual’s private activities leave little inclination to engage actively in politics, entrusting the business of law-making to representatives, a more ‘passive’ approach.
If the liberal model of citizenship dominates sovereign constitutional democracies, then the republican critique of the private citizen’s passivity is still alive. Therefore, instead of opposing the two models, we could reasonably see them as complementary. Michael Walzer illustrates that the two conceptions “go hand in hand” since “the security provided by the authorities cannot just be enjoyed; it must itself be secured, and sometimes against the authorities themselves. The passive enjoyment of citizenship requires, at least intermittently, the activist politics of citizens”. This means that there are times when individuals only temporarily need to be “private citizens” and others when they must become “private citizens” (Ackermann 1988).
Globalisation and Citizenship
Conceptions of citizenship have had one thing in common, the idea that the necessary framework for citizenship is created by the sovereign, territorial state. The legal status of a citizen is the formal manifestation of membership in the sovereign state. Within these borders citizens enjoy equal rights and exercise their political agency which creates a common identity. This premise has come under close scrutiny with continued globalisation, and have encouraged a critical awakening which has massively increased transnational economic exchange, competition and high levels of migration, including cultural and social interactions. It is arguable that this has cause the demise of some of the Traditional Knowledge and Genetic Resources in a sovereign nation. Globalization has further illustrated how porous borders have become and led people to contest the relevance and legitimacy of state sovereignty. This has introduced the philosophy of citizenship potentially being both a legal status, and as an economic activity. This is exemplified in the increased use of Commonwealth Citizenship by Investment Programmes (CICIP) by sovereign governments seeking new avenues to foreign investment.
Whether citizenship is understood in terms of civic self-government (republican version) or as the ability to exercise control over government (liberal version), it is not yet easy to determine how citizens can exercise meaningful political agency in very complex societies. This difficulty is exemplified in the global debate over the long-term sustainability of transnational citizenship and/or investment migration programmes.
 Kymlicka and Norman 1994  Benhabib, S., 2004, The Rights of Others. Aliens, Residents and Citizens, Cambridge: Cambridge University Press.