The 14th Amendment to the U.S. Constitution, adopted 144 years ago on July 9, provides for the grant of birthright citizenship to the American‐​born children of unauthorized immigrants and lawful immigrants with various forms of residency. Despite the current controversy around this provision, the 14th Amendment is unintentionally successful as a policy for assimilating the children of immigrants.

Immigrants to the U.S. assimilate very quickly. Speaking of America’s openness to immigrants, former President Ronald Reagan stated, “An immigrant can live in France but not become a Frenchman; he can live in Germany but not become a German; he can live in Japan but not become Japanese, but anyone from any part of the world can come to America and become an American.” Americans, immigrants, and their descendants become Americans. Our system of birthright citizenship makes “Americanization” even easier.

Today, in some respects, they assimilate even more rapidly than previous immigrant waves such as the Irish. What happens to societies that accept large numbers of immigrants but don’t extend birthright citizenship to children is a warning of what could happen here if birthright citizenship is ever discontinued.

First, a little bit of history. The 14th Amendment, enacted in the aftermath of the Civil War, included the citizenship clause to overrule the 1857 Supreme Court Dred Scott v. Sandford decisionthat in part stated that black Americans could never become citizens.

The citizenship clause of the 14th Amendment reads: “All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.”

During the debate, it was understood that the citizenship clause would extend to the children of immigrants who were, under the existing immigration law, unable to naturalize, such as Asians and other nonwhite immigrants.

Sen. Jacob Howard, R‑Mich., introduced the citizenship clause. During Senate debate, he said it “will not, of course, include persons in the United States who are foreigners, aliens, who belong to the families of ambassadors or foreign ministers accredited to the Government of the United States, but will include every other class of persons.” (Emphasis added.)

The U.S. rule of birthright citizenship offers a stark contrast to policies pursued in Germany and Japan, where the children of immigrants were denied citizenship.

The German guest‐​worker program of the 1950s through the 1970s admitted large numbers of Turks, Tunisians, Portuguese, and others to work in the 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 nation 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 communism.

At about the same time Germany started to allow in Turks as guest workers, it also created its Aussiedler system to “repatriate” 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 around 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.

Youths born to noncitizen immigrants in nations without birthright citizenship have little legal stake in the nations they were born in but also have no place to go. Many might gain citizenship through the ethnicity of their parents in Korea or Turkey, but with no connections to those nations, citizenship there is meaningless.

In the U.S., by contrast, children of immigrants are legally on the same playing field as children born to American citizens. Both can serve in the military, purchase firearms, serve on juries, and be treated the same by the legal system. That is one reason why 89 percent of second‐​generation Hispanics and 96 percent of third‐​generation Hispanics have described themselves as American only. “Hispanic‐​American” or “Mexican‐​American” is still popular among some after several generations, just as “Italian‐​American” still survives, but these Americans do not view themselves as foreigners.

The likelihood of amending the 14th Amendment’s citizenship clause is small, but it should be defended because of how well it has helped jump‐​start immigrant assimilation in the U.S. Remembering the 14th Amendment as a correction to previous racist policies is essential, but that history should not blind us to its pro‐​assimilation impact.