Nationality in International Law is the legal relationship between an individual and a State that establishes the personβs membership in that State and creates reciprocal rights and obligations. Nationality is particularly important in matters of diplomatic protection, jurisdiction, State responsibility, extradition and protection of nationals abroad.
- Meaning of Nationality
- Nationality and International Law
- Nationality and Citizenship
- Importance of Nationality
- Acquisition of Nationality
- Naturalisation
- Registration
- Marriage
- Adoption
- Loss of Nationality
- Deprivation of Nationality
- Statelessness
- Convention on the Reduction of Statelessness, 1961
- Right to Nationality
- Nationality of Married Women
- Dual Nationality
- Problems of Dual Nationality
- Effective Nationality
- Nottebohm Case
- Importance of Nottebohm
- Barcelona Traction and Nationality
- Nationality and Diplomatic Protection
- Continuous Nationality
- Nationality and Jurisdiction
- Active Nationality Principle
- Nationality and Extradition
- Nationality and Protection Abroad
- Nationality and International Claims
- Nationality and State Succession
- Nationality and Human Rights
- Nationality and Refugees
- Nationality and International Legal Personality
- Limits on State Discretion
- Important Cases
- Common Confusions
- Topic at a Glance
- Quick Revision
- Conclusion
Meaning of Nationality
Nationality is the legal bond between a person and a State.
It determines the State to which an individual belongs for purposes of International Law.
The relationship may be represented as:
Individual β State
Nationality generally gives the State the right to:
- protect its nationals abroad;
- exercise jurisdiction over them in appropriate circumstances;
- provide diplomatic protection;
- confer political and civil rights under domestic law.
At the same time, the national may owe obligations to the State, such as duties imposed by domestic law.
Nationality and International Law
Nationality is primarily regulated by domestic law, but International Law places limits on how States exercise their power concerning nationality.
A State generally determines:
- who its nationals are;
- how nationality is acquired;
- how nationality is lost;
- whether dual nationality is permitted;
- procedures for naturalisation.
However, nationality may have international consequences, particularly where one State seeks to invoke the nationality of a person against another State.
Nationality and Citizenship
The terms nationality and citizenship are often used interchangeably, but they can have slightly different meanings.
Nationality
Refers primarily to the legal bond between an individual and a State under domestic and International Law.
Citizenship
Often refers to membership in a State and the rights associated with that membership, particularly political rights.
In International Law, nationality is generally the more important term.
Importance of Nationality
Nationality performs several important functions in International Law.
It determines:
- which State may exercise diplomatic protection;
- which State may protect an individual abroad;
- the nationality of persons for certain jurisdictional purposes;
- whether a person is a national or foreigner;
- the State to which certain international claims may be attributed.
Acquisition of Nationality
Nationality can generally be acquired through several methods.
Nationality by Birth
A person may acquire nationality at birth.
Two major principles are:
Jus soli
and
Jus sanguinis
Jus Soli
Jus soli means βright of the soil.β
Nationality is acquired based on birth within the territory of a State, subject to that Stateβs domestic law.
Jus Sanguinis
Jus sanguinis means βright of blood.β
Nationality is acquired through descent from parents who possess the nationality of the State.
Thus:
Jus soli β place of birth
Jus sanguinis β nationality of parents
States may use either principle or a combination of both.
Naturalisation
A person may acquire nationality through naturalisation.
Naturalisation is the legal process through which a foreign national becomes a national of another State.
Conditions may include:
- residence;
- language requirements;
- knowledge of the countryβs legal or political system;
- good character;
- formal application;
- renunciation of previous nationality in some States.
The exact requirements are determined by domestic law.
Registration
Some States permit nationality to be acquired through registration under specified legal conditions.
This may apply to:
- persons with parental connections;
- spouses;
- persons born abroad;
- persons with historical connections to the State.
Marriage
Marriage may sometimes facilitate acquisition of nationality.
However, modern International Law does not generally require a State to automatically confer nationality on a foreign spouse.
Domestic law determines the applicable conditions.
Adoption
Nationality may sometimes be acquired through adoption where the domestic law of the relevant State provides for it.
Loss of Nationality
Nationality may be lost through:
- voluntary renunciation;
- withdrawal under specific domestic law;
- acquisition of another nationality in certain legal systems;
- other circumstances recognised by domestic law.
International Law places limits on arbitrary deprivation of nationality.
Deprivation of Nationality
A State may, under its domestic law, deprive a person of nationality in certain circumstances.
However, nationality cannot simply be removed arbitrarily without regard to applicable International Law.
Particular concerns arise where deprivation would result in statelessness or discrimination.
Statelessness
A stateless person is an individual who is not considered a national by any State under the operation of its law.
Statelessness can result from:
- conflicting nationality laws;
- changes in State boundaries;
- discriminatory nationality laws;
- deprivation of nationality;
- gaps in domestic legislation.
Stateless persons may face difficulties concerning:
- travel;
- employment;
- education;
- residence;
- political rights;
- diplomatic protection.
Convention on the Reduction of Statelessness, 1961
The 1961 Convention on the Reduction of Statelessness seeks to reduce cases of statelessness and establish safeguards against its occurrence.
Right to Nationality
The right to nationality is recognised in major international human rights instruments.
Article 15 of the Universal Declaration of Human Rights provides that:
- everyone has the right to a nationality;
- no one should be arbitrarily deprived of nationality;
- no one should be arbitrarily denied the right to change nationality.
This demonstrates that nationality is not regarded as an entirely unrestricted matter of domestic discretion.
Nationality of Married Women
Historically, marriage could automatically affect a womanβs nationality.
Modern International Law has moved away from automatic changes of nationality based solely on marriage.
The Convention on the Nationality of Married Women, 1957 seeks to prevent nationality rules from automatically changing merely because of marriage.
Dual Nationality
A person may possess the nationality of two or more States.
This can arise where:
- one State applies jus soli;
- another applies jus sanguinis;
- a person acquires a second nationality through naturalisation;
- domestic nationality laws overlap.
For example:
Born in State A β nationality under jus soli
Parents are nationals of State B β nationality under jus sanguinis
The person may therefore possess both nationalities.
Problems of Dual Nationality
Dual nationality may create questions concerning:
- diplomatic protection;
- military obligations;
- taxation;
- diplomatic protection against the other State of nationality;
- jurisdiction;
- conflicting national obligations.
Effective Nationality
Where an individual possesses more than one nationality, International Law may sometimes consider which nationality is effective or genuine in the circumstances.
Factors may include:
- habitual residence;
- family connections;
- centre of interests;
- participation in public life;
- actual attachment to the State.
Nottebohm Case
The leading case is:
Nottebohm (Liechtenstein v. Guatemala), 1955
Friedrich Nottebohm was originally closely connected with Germany but acquired Liechtenstein nationality.
Liechtenstein attempted to exercise diplomatic protection against Guatemala.
The ICJ held that the nationality relied upon by Liechtenstein could not be invoked against Guatemala in the circumstances because the nationality did not reflect a sufficiently genuine connection for the purpose of diplomatic protection.
Importance of Nottebohm
The case is particularly important for the concept of effective or genuine nationality.
However, its application should not be misunderstood as establishing that every nationality must always satisfy a universal βgenuine connectionβ test.
The case is particularly significant in the context of diplomatic protection.
Barcelona Traction and Nationality
Nationality is also important for corporations.
In Barcelona Traction, Light and Power Company, Limited (Belgium v. Spain), 1970, the ICJ considered the nationality of a company for purposes of diplomatic protection.
The Court recognised the importance of the State of incorporation/nationality of the company when determining which State could exercise diplomatic protection for injury to the corporation itself.
Nationality and Diplomatic Protection
Nationality is a fundamental requirement for diplomatic protection.
The basic principle is:
National of State A
β
Injury caused by State B
β
State A may exercise diplomatic protection
subject to applicable requirements, including the exhaustion of local remedies.
Continuous Nationality
For diplomatic protection, the nationality of the injured person must generally continue through the relevant stages of the claim.
This is known as the continuous nationality principle.
The requirement seeks to prevent a State from acquiring a diplomatic protection claim simply by granting nationality after the injury has occurred.
Nationality and Jurisdiction
Nationality can also serve as a basis for the exercise of State jurisdiction.
Under the nationality principle, a State may exercise jurisdiction over its nationals for certain conduct occurring outside its territory, subject to applicable International Law.
Thus:
Nationality β Personal jurisdiction
This is particularly relevant to criminal jurisdiction.
Active Nationality Principle
The active nationality principle allows a State to exercise jurisdiction over offences committed by its nationals outside its territory.
For example:
National of State A β commits offence abroad
β
State A may exercise jurisdiction under its domestic law
The extent to which such jurisdiction is permissible depends upon International Law and the relevant domestic legislation.
Nationality and Extradition
Nationality may become relevant in extradition cases.
Some States follow the principle that they may refuse to extradite their own nationals and instead prosecute them domestically.
Other States permit extradition of nationals subject to applicable conditions.
Therefore:
Nationality β may influence extradition
but does not automatically prevent extradition in every legal system.
Nationality and Protection Abroad
A State may provide consular assistance to its nationals abroad.
However, consular assistance and diplomatic protection are distinct.
Consular assistance β practical assistance
Diplomatic protection β invocation of international responsibility
Nationality is relevant to both.
Nationality and International Claims
Nationality can determine whether a State has standing to bring certain international claims on behalf of an individual.
This is particularly important in diplomatic protection.
Nationality and State Succession
State succession can create difficult nationality questions.
When a State:
- dissolves;
- separates;
- merges;
- transfers territory;
individuals may acquire, lose or change nationality.
International Law seeks to reduce cases of statelessness arising from State succession.
Nationality and Human Rights
Nationality is connected with several fundamental rights.
International law seeks to prevent:
- arbitrary deprivation of nationality;
- discrimination in nationality matters;
- unnecessary creation of statelessness.
Nationality may also affect rights concerning:
- political participation;
- residence;
- entry into the State;
- diplomatic protection.
Nationality and Refugees
Refugees may retain the nationality of their State of origin while receiving protection in another State.
A refugeeβs nationality and refugee status are therefore distinct concepts.
Nationality β legal bond with a State
Refugee status β international protection because of circumstances in the State of origin
Nationality and International Legal Personality
Nationality does not make an individual a State or automatically give the individual the same international legal personality as a State.
However, modern International Law recognises individuals as holders of certain international rights and obligations.
Nationality remains important for determining the relationship between the individual and a particular State.
Limits on State Discretion
States possess broad authority to determine nationality under their domestic law.
However, this authority is not unlimited in its international consequences.
States must take into account applicable:
- treaties;
- customary International Law;
- human rights obligations;
- rules concerning statelessness;
- obligations arising from diplomatic protection.
Important Cases
Nottebohm (1955)
Important for nationality and genuine/effective connection in diplomatic protection.
Barcelona Traction (1970)
Important for nationality of corporations and diplomatic protection.
MergΓ© Claim (1955)
Important for dual nationality and effective nationality.
Ahmadou Sadio Diallo (2010)
Important for nationality and diplomatic protection concerning individuals and corporate interests.
Common Confusions

Is nationality entirely a matter of domestic law?
States determine nationality under domestic law, but International Law regulates the international consequences and places certain limits on State discretion.
What is jus soli?
Nationality based principally on place of birth.
What is jus sanguinis?
Nationality based principally on descent.
What is naturalisation?
Acquisition of nationality after birth through a legal process established by domestic law.
What is statelessness?
A condition in which a person is not considered a national by any State under its law.
Can a person have two nationalities?
Yes. Dual nationality is possible under overlapping nationality laws.
What is effective nationality?
The nationality that may be regarded as genuine or predominant in particular circumstances, especially in cases involving competing nationalities.
What is the leading case?
Nottebohm (Liechtenstein v. Guatemala), 1955 is the leading case concerning nationality and diplomatic protection.
Why is nationality important in diplomatic protection?
Because the State generally must establish that the injured person is its national before exercising diplomatic protection.
Topic at a Glance
Point Position Meaning Legal bond between individual and State Main basis Domestic law subject to International Law Jus soli Nationality based on birth/place of birth Jus sanguinis Nationality based on descent Naturalisation Acquisition after birth Statelessness No nationality of any State Dual nationality Nationality of two or more States Effective nationality Genuine/predominant nationality in relevant circumstances Diplomatic protection Nationality is central Continuous nationality Important for diplomatic protection Jurisdiction Nationality may provide personal jurisdiction Extradition Nationality may affect extradition State succession Can create nationality problems Leading case Nottebohm, 1955 Corporate nationality Barcelona Traction, 1970
Quick Revision
- Nationality is the legal bond between an individual and a State.
- States generally determine nationality through their domestic law, subject to International Law.
- Main methods of acquisition include:
- jus soli;
- jus sanguinis;
- naturalisation;
- registration;
- other domestic procedures.
- Jus soli β nationality based on place of birth.
- Jus sanguinis β nationality based on descent.
- Statelessness β person is not considered a national by any State.
- Dual nationality β person possesses two or more nationalities.
- Nationality is particularly important for diplomatic protection.
- The continuous nationality principle is relevant to diplomatic protection.
- The nationality principle can provide a basis for jurisdiction over nationals.
- Nationality may also affect extradition.
- Nottebohm (1955) β genuine/effective nationality.
- Barcelona Traction (1970) β nationality of corporations.
- MergΓ© Claim (1955) β dual nationality.
- Diallo (2010) β nationality and diplomatic protection.
- The essential principle is:
Nationality establishes the legal bond between an individual and a State and serves as an important basis for diplomatic protection, personal jurisdiction and other rights and obligations under International Law.
Conclusion
Nationality is a fundamental concept in International Law because it establishes the legal relationship between an individual and a State. Although States generally determine the acquisition and loss of nationality through their domestic laws, their decisions may have important international consequences and are subject to applicable International Law. Nationality may be acquired through jus soli, jus sanguinis, naturalisation, registration and other domestic mechanisms. Problems may arise through dual nationality, statelessness, changes in nationality and State succession. Nationality is particularly important in diplomatic protection, where the State generally must establish the nationality of the injured person before invoking the international responsibility of another State. The Nottebohm case is central to the discussion of genuine or effective nationality, while Barcelona Traction is important for corporate nationality. Nationality can also serve as a basis for the exercise of personal jurisdiction and may influence extradition and consular protection. Modern International Law also seeks to prevent arbitrary deprivation of nationality and reduce statelessness. Thus, nationality operates as a crucial connecting factor between the individual, the State and the international legal system.
