Every country has its own set of citizenship laws, which may include the following provisions:
Prohibition of dual citizenship:
In some countries, such as Belarus, Estonia, the Netherlands, Montenegro, Germany, Austria, and Kazakhstan, obtaining dual citizenship is strictly prohibited. This prohibition often results in the loss of rights associated with the original passport. Individuals acquiring a new passport may lose their voting rights, access to benefits and social payments, and may require permission for tourist entry into the country.
In Kazakhstan, for example, active control is exercised over compliance with this prohibition, and penalties and deportation may result from non-compliance. In Belarus, this prohibition is rarely enforced, especially if the individual has not served in the military or civil service of another country.
There are exceptions: for example, Germany allows obtaining a second EU or Swiss passport, and Montenegro allows obtaining Macedonian citizenship under the "Citizenship by Investment" program, allowing investors to retain their original documents.
Permission for dual citizenship:
In countries like Russia, the United States, Cyprus, Turkey, Portugal, and Vanuatu, citizens can obtain additional passports while retaining their original citizenship. This is known as dual citizenship. Although some rights may be limited, obligations to the home country are generally preserved.
In Russia, for instance, acquiring dual citizenship means losing the possibility of becoming president or entering government service, but individuals can still claim benefits, vote in elections, and exercise other rights.
It is important to note that where dual citizenship is permitted, an individual may acquire third (and more) citizenships if allowed by the legislation of each country.
Agreements on dual citizenship:
Some countries have agreements on dual citizenship with specific states. According to these agreements, certain obligations and rights may be coordinated. For example, a military service member may fulfill duties in either of the two countries whose passport they hold.
Russia has a dual citizenship treaty with Tajikistan, Spain with Argentina, Chile, Peru, and other Latin American territories. However, the US does not have such agreements.
It is essential to note that dual citizenship and second citizenship are different concepts, each with its own implications and peculiarities. Understanding the differences between them is crucial for those navigating the complexities of international citizenship.