The U.S. rule of birthright citizenship offers a stark contrast to policies pursued in Germany and Japan, where the children of immigrants are either denied citizenship or face a much harder path toward obtaining it.

The German guest-worker program of the 1950s through the 1970s admitted large numbers of Turks, Tunisians, Portuguese, and others to work in their growing economy. Originally, the Germans had no intention of letting the workers and their families stay permanently, but many, especially the Turks, did stay. Their German-born children were not allowed to become citizens. The same was true in Japan, where the Korean minority, called zainichi, was barred from citizenship for generations despite being born in Japan.

In both countries, the results were tragic. The lack of birthright citizenship created a legal underclass of resentful and displaced young people who were officially discriminated against in the government-run education system and had tenuous allegiance to the country in which they were born. After four generations in Japan, ethnic Koreans still self-identify as foreign. In both countries, these noncitizen youths are more prone to crime and extreme political ideologies like Islamism or communism.

Their failure to naturalize the Turks contrasts with Germany’s Aussiedler system that “repatriated” ethnic Germans and their families living in the territory of the Soviet Union, immediately granting them citizenship by virtue of their blood connection to Germany. Aussliedler inflows peaked in the late 1980s and early 1990s, when approximately 2.2 million ancestral Germans were admitted and given citizenship. Germany partly rectified its system in 1999, extending citizenship to Turks and creating some legal categories that can gain citizenship through birthright.