Can U.S. citizens maintain dual citizenship with another country?
Multiple citizenship
If the parents of a child have different citizenships or are multiple citizens themselves, the child may gain multiple citizenship depending on whether and how jus soli and jus sanguinis apply for each citizenship. Some countries (e.g., Canada, the United States of America and many other countries in the Americas) regard all children born there automatically to be eligible to be citizens (jus soli) even if the parents are not legally present. For example, a child born in the United States to Norwegian parents automatically has dual citizenship with the United States and Norway, even though Norway usually restricts or forbids dual citizenship. There are exceptions, such as the child of a foreign diplomat living in the United States. Such a child would be eligible to become a lawful permanent resident, but not a citizen based on the U.S. birth.[29]This has led to birth tourism, so some countries have abolished jus soli or restricted it (i.e., at least one parent must be a citizen or a legal, permanent resident who has lived in the country for several years). Some countries forbid their citizens to renounce their citizenship or try to discourage them from doing so.[12] Policy changes may also render people to have multiple citizenship involuntarily, for example, when the sovereignty of a place is changed, the new country may declare the people on it to be citizens of the country.
Birth tourism
The United States, Canada, and Mexico all grant unconditional birthright citizenship and allow dual citizenship. The United States taxes its citizens and green card holders worldwide, even if they have never lived in the country. In Mexico, only naturalized citizens can lose their Mexican citizenship again (e.g., by naturalizing in another country). 