Countries forbidding dual citizenship overall are not only more populated, they’re poorer. High-income countries are more likely to allow dual citizenship.

Nordic countries, such as Sweden, Denmark, and Iceland, are among the wealthiest countries that allow citizens to have another citizenship. Norway is the richest country that forbids dual-citizenship. The Norwegian government, however, has recently put together a proposal to join their rich neighbors to allow it.

Most dual-citizenship-forbidding countries have smaller foreign-born populations. China, Cuba and Indonesia, for example were 0.07%, 0.11% and 0.13% foreign-born in 2017, respectively. But there are exceptions. The United Arab Emirates, which doesn’t recognize dual citizenship, has 88% of its population foreign-born. Migrant workers flock to the Gulf state for higher-paying jobs than those at home, but they are not allowed to naturalize.

Vietnam started recognizing dual citizenship in 2008, one year after the country joined the World Trade Organization. Philippines changed its law in 2003 to allow dual citizenship. Both places have small shares of foreign-born population today. Since 2005, the share of foreign-born population in Vietnam increased from 0.06% to 0.08%, while that of Philippines has shrunken from 0.3% to 0.2%.

Countries’ democratic levels have little to do with their dual-citizenship policies. Syria and North Korea took the bottom spots among the 165 countries in the rankings of 2017 Democracy Index. Syria allows dual citizenship; North Korea forbids. The most democratic country on the Index, Norway, does not recognize dual citizenship.

While more than half of the world’s population would have to give up the citizenship of their home country to get a new one, an increasing number of countries across all continents have loosened dual citizenship policies over time.

Among the latest countries to permit dual-citizenship, Denmark changed its policy in 2015. Brexit also made some European countries act. Germany, for example, proposed a bill, allowing Brits who acquire German citizenship after Brexit to retain their British ones.

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