Definition and Explanation of Terms: Dual National
The term dual national refers to a person who holds the nationality of at least two countries at the same time. The status of a dual national affects numerous aspects of national and international law, particularly with regard to nationality law, residency, military service, duties of protection, and rights relating to legal status in the respective countries. The legal provisions and consequences of dual nationality vary depending on the countries involved, intergovernmental agreements, and international guidelines.
Origin of Dual Nationality
Original acquisition of dual nationality
Dual nationality often arises from the application of different nationality principles, such as the principle of place of birth (jus soli) and the principle of descent (jus sanguinis). For example, if a child is born to parents of different nationalities or on the territory of a state different from their parents’, they may acquire multiple nationalities from birth.
Acquisition through naturalization
Dual nationality can also arise through naturalization if the country of naturalization does not require the renunciation of the previous nationality or if the country of origin does not provide for, or makes it difficult to, lose the old nationality.
Other reasons for acquisition
Other possibilities include acquisition through marriage, adoption, or reacquisition of a former nationality. Additionally, through the so-called “option requirement”—for example, under certain German regulations—dual nationality may exist temporarily.
Legal bases of dual nationality
National law
Many countries have specific rules for the recognition, toleration, or rejection of multiple nationalities. While countries like Germany take a restrictive approach and permit dual nationality only in exceptional cases, other countries such as France or Switzerland generally accept the status of dual nationals.
International agreements
International agreements such as the European Convention on the Reduction of Cases of Multiple Nationality (1963) and the Convention on Nationality under the Council of Europe (1997) are intended to regulate the consequences of multiple nationality or to prevent its occurrence. The effects and binding force of such agreements depend on which countries have ratified them.
European law
In the context of the European Union, EU citizenship plays a significant role. It does not replace national citizenship, but rather supplements it. Rights such as freedom of movement, the right to vote and stand for election in European elections, and consular protection by other member states affect dual nationals within the EU in particular.
Legal consequences of dual nationality
Military service and conscription
A key aspect is compulsory military service: Dual nationals may be subject to conscription in both countries. International agreements, such as the “European Convention on Nationality” and bilateral treaties, often provide exceptions to avoid double obligations. In practice, however, differing national interests may occasionally lead to conflicts or double obligations.
Rights and obligations towards both countries
Dual nationals enjoy the rights and are subject to the obligations of both countries. These include taxation, social security, voting rights, and civic duties. Conflicts may arise if laws contradict each other, such as with compulsory military service or obligations for certain conduct in the public sector.
Consular protection and diplomatic representation
In principle, dual nationals are entitled to consular protection from both countries. However, many countries exclude consular protection on their own territory for persons with an additional nationality. Diplomatic protection in relation to third countries can also be complex, as it is not always clear which country is responsible for protecting its dual nationals.
Loss and Renunciation of Dual Nationality
Automatic loss or withdrawal
Some countries provide for the automatic loss of previous nationality upon acquisition of a new one. Status may also be lost through revocation of nationality, such as for serious offenses. The prerequisites and procedures for withdrawal are usually strictly regulated and subject to international human rights standards, as statelessness is to be avoided.
Voluntary renunciation
Dual nationals can usually voluntarily renounce one of their nationalities if permitted by the law of the respective country. The renunciation must be formally declared and approved by the competent authority.
Dual nationals in the international context
Statelessness and state connections
The status of dual nationality is intended to prevent statelessness, but in the international context it brings a variety of legal challenges, particularly concerning deportation, extradition, and the fulfillment of civic duties in different countries.
Tax law aspects
Dual nationals are sometimes in the focus of international tax law. Double taxation agreements determine which country has the right to tax certain income or assets. Complexities can arise, for example, in the case of a change of residence or cross-border economic activities.
Conclusion – The significance of dual nationals in the legal system
The legal status of dual nationals is highly complex, as it is influenced by both national and international law and changing arrangements between the countries concerned. Central issues include military duties, taxation, diplomatic protection, and participation in public life. Constantly evolving laws and international agreements make the status of dual nationals flexible, but also challenging, especially in an increasingly interconnected and globalized world.
Frequently Asked Questions
What obligations does a dual national have towards the countries involved?
A dual national—that is, a person who possesses the nationality of two different countries—is generally subject to the legal obligations of both countries. This means that laws such as tax liability, compulsory military service, registration requirements, or duties to cooperate with state institutions must be fulfilled in both countries, unless there are special international legal regulations or bilateral treaties providing for relief or excluding certain obligations. In the case of military service, bilateral agreements—such as those Germany has concluded with some countries—can prevent dual conscription. The situation is especially complex if the countries concerned are in conflict with each other or have different requirements with regard to compliance with regulations. Typically, it is not possible to invoke the “other” nationality to circumvent obligations in either country. Thus, dual loyalty conflicts are fundamentally possible, especially since international law does not provide universal solutions for such cases, but relies on international agreements or individual case decisions.
What impact does acquiring an additional nationality have on existing citizenship?
The acquisition of an additional nationality can have different consequences depending on the national law of the country of origin. Some countries provide for the automatic loss of the original nationality upon acquiring a new one (so-called “automatic loss”), while others allow multiple nationalities or make retention dependent on prior approval. In Germany, for example, acquiring a foreign nationality generally leads to the loss of German citizenship unless a retention permit was applied for and granted beforehand. Austria, by contrast, recognizes multiple nationalities only in a few exceptional cases, whereas many Western countries—such as France, the United Kingdom, or Canada—generally tolerate dual nationality. A careful examination of the national laws of both countries and any special provisions or notification requirements is essential for those affected, as unintended loss of nationality can have far-reaching consequences (e.g., loss of residence or voting rights).
Can dual nationals participate in elections and hold public office in both countries?
Whether and to what extent a dual national may exercise active or passive voting rights and the right to hold public office (such as access to the civil service) in both countries depends on the respective national regulations. In many cases, the right to vote is tied to both nationality and residence. In Germany, German citizens—including dual nationals—are generally entitled to participate in all Bundestag, state, and local elections, or to hold public office, provided they meet other requirements (e.g., minimum age, suitability). Other countries may impose restrictions, for example, excluding dual nationals from the diplomatic service or from security-related positions. In some countries, the right to vote for those residing abroad is limited or excluded. Therefore, it is necessary to be familiar with the legal requirements of both countries and to observe possible incompatibilities.
Are dual nationals required to perform military service in both countries in an emergency?
The obligation to perform military service for dual nationals depends on the legal requirements of the countries concerned. In theory, it is possible that both countries may demand military service from the same person. To prevent double conscription, some countries have bilateral or multilateral agreements that lead to mutual crediting of already completed service or provide for compulsory service only in the country of residence. Germany, for example, maintains such agreements with numerous countries (for example, the USA, Switzerland, or Turkey), which protect dual nationals from being conscripted twice. In the absence of such agreements, however, the obligation can actually exist to serve in both countries or suffer disadvantages if service is refused in one country (e.g., entry bans, criminal consequences).
What legal options exist for renouncing a nationality?
The procedure for renouncing a nationality is regulated differently depending on the country. In Germany, nationality can be renounced on application by being released from the association with the state, provided the person concerned holds at least one other nationality and there are no specific obstacles such as compulsory military service, ongoing investigations, or outstanding obligations to the state. The process involves extensive documentation requirements and, in certain cases, such as a nationality of an EU member state, additional checks. Other countries may have more restrictive regulations or even prohibit renunciation, for example if security or tax interests are concerned or if renunciation would lead to statelessness. It is advisable to seek legal advice early on and carefully review national requirements to avoid legal or societal disadvantages.
Can dual nationals abroad claim diplomatic protection from both countries?
In principle, dual nationals are entitled under international law, particularly under the Vienna Convention on Diplomatic Relations, to diplomatic protection from the country whose nationality they possess—subject to one important limitation: If they are in the country of their other nationality, they cannot claim diplomatic protection from the other home country. In third countries, diplomatic protection by both nations may be requested, but actual provision also depends on political and practical considerations. Furthermore, many countries exclude consular assistance for their dual nationals when they are in the territory of the other home country. In some cases, dual nationality can result in legal uncertainties or restricted protection, for example if third countries interpret diplomatic status differently.
Are there tax consequences for dual nationals?
Dual nationals are generally subject to taxation pursuant to the laws of both countries, provided these apply the worldwide income principle or income is earned in the respective country. Double Taxation Agreements (DTAs) between most industrialized nations determine which country has the right to tax, with the aim of preventing double taxation and granting dual nationals legal certainty. Nevertheless, complex situations—such as changes of residence, inheritances, or business interests—can require that certain income be declared in both countries, with taxes paid in one country credited against the tax owed in the other (credit method) or, exceptionally, certain types of income taxed only in one country (exemption method). Correct compliance with notification obligations and detailed tax advice are therefore essential for dual nationals, as false statements can lead to criminal proceedings or financial disadvantages.
