Between 1995 and 2010, the number of people in the Netherlands with dual citizenship nearly tripled. That isn’t surprising, considering that globalization has made countries all over the world more receptive to the idea of people having more than one nationality.

What is surprising is that the Netherlands is one of the few countries in the world now trying to scale this back, having introduced a law last year that makes it harder for both immigrants to the Netherlands and emigrants from the Netherlands to hold onto their first nationality, as the far-right Freedom Party sees dual citizenship as a threat to national loyalty and as an impediment to assimilation in the Netherlands.

“More than half of the states in the world -- countries of immigration as well as emigration -- now tolerate some form or element of dual citizenship,” reported a study by the Migration Policy Institute, a nonpartisan think tank based in the US. As the Economist pointed out, countries like Haiti and Tanzania are among the latest to work toward legalizing dual nationality. And even Denmark, which has long been one of the most difficult places to get dual citizenship – typically only granting it to refugees, those who were born with dual nationality, or those who were not able to renounce their first citizenship – is considering moving toward greater acceptance of the trend.

In the past, governments believed that the desire to belong to more than one nation was an expression of disloyalty. More recently, lingering concerns have been over whether immigrants can fully assimilate if they cling to their original nationality. But census data seems to discredit this theory. For example, in the US (which began passing laws tolerating dual citizenship in the 1950s), the numbers show that Latin American immigrants who become dual citizens have greater employment gains and lower welfare use than those who become US citizens but let go of their first citizenship, indicating economic assimilation. In addition, these immigrants give birth to fewer children than their counterparts, possibly indicating cultural assimilation.

Moreover, some governments have found ways to directly benefit from dual citizenship. Italy used dual nationality as a way to fight its declining population in the 1990s. The current law grants birthright citizenship to anyone with a parent, a grandfather or a great grandfather who held Italian citizenship. Two Caribbean nations, Dominica and St Kitts and Nevis, have “economic citizenship programs” which allow people to buy citizenship without any residency requirements. While those are the only countries in the world selling citizenship directly, in the Dominican Republic, foreigners who invest in real estate or local businesses can obtain citizenship after a minimum residency of just six months (as opposed to the standard two years that other people would have to wait).

For individuals considering taking a second citizenship, the advantages include expanded job opportunities, unrestricted residency, the ability to own property in two countries, access to social programs in two countries and the increased travel options that come with having two passports. Dual citizens may have double the responsibilities though too. Some dual citizens may have to pay taxes and/or register for military service in their new countries -- for instance, South Korea allows dual citizenship until the age of 21 and requires men over the age of 18 to complete military service. In addition, immigrants who gain local citizenship may be subject to laws that would not apply to them as tourists. Citizenship regulations vary quite a bit from country to country, so prospective dual citizens should review their countries’ laws before making a final decision on the matter.

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