Citizenship is the relationship between an individual and a state to which the individual owes allegiance and in turn is entitled to its protection. Citizenship implies the status of freedom with accompanying responsibilities. Citizens have certain rights, duties, and responsibilities that are denied or only partially extended to aliens and other noncitizens residing in a country. In general, full political rights, including the right to vote and to hold public office, are predicated upon citizenship. The usual responsibilities of citizenship are allegiance, taxation, and military service.
Citizenship is the most privileged form of nationality. This broader term denotes various relations between an individual and a state that do not necessarily confer political rights but do imply other privileges, particularly protection abroad. It is the term used in international law to denote all persons whom a state is entitled to protect. Nationality also serves to denote the relationship to a state of entities other than individuals; corporations, ships, and aircraft, for example, possess a nationality.
The principal grounds for acquiring citizenship (apart from international transactions such as transfer of territory or option) are birth within a certain territory, descent from a citizen parent, marriage to a citizen, and naturalization. There are two main systems used to determine citizenship as of the time of birth: jus soli, whereby citizenship is acquired by birth within the territory of the state, regardless of parental citizenship; and jus sanguinis, whereby a person, wherever born, is a citizen of the state if, at the time of his or her birth, his or her parent is one. The United States and the countries of the British Commonwealth adopt the jus soli as their basic principle; they also recognize acquisition of nationality by descent but subject it to strict limitations. Other countries generally adopt the jus sanguinis as their basic principle, supplementing it by provisions for acquisition of citizenship in case of combination of birth and domicile within the country, birth within the country of parents born there, and so on. The provisions of nationality laws that overlap often result in dual nationality; a person may be a citizen of two countries. Alternatively, the lack of uniform rules on citizenship acquisition and loss have sometimes produced lack of citizenship (statelessness).
Adevara Adetomiwa, Sumy State University