Viktor and Amalija Knavs listen as their attorney makes a statement in New York on Aug. 9. First lady Melania Trump's parents have been sworn in as U.S. citizens. (Seth Wenig/AP)

President Trump has long railed against “chain migration” and continues to threaten to end family-preference immigration visas, despite the fact that his in-laws Viktor and Amalija Knavs were granted U.S. citizenship through the first lady’s sponsorship.

But Trump did not originate attacks on chain migration. The anti-immigration lobby with the mendacious acronym FAIR (Federation of American Immigration Reform) has been denouncing chain migration on its website for more than a decade, arguing that current policy has made U.S. immigration less meritocratic, because “most migrants receive a green card simply because they are the relative of an earlier migrant, not because of what they can contribute to American society.”

Whether through ignorance or intent, FAIR unfairly stigmatizes what has been a normal feature of migration to the United States and around the world for centuries. Chain migration was the predominant form of immigration long before there were visa policies favoring it, and it played a vital role in easing culture shock and promoting acculturation across the centuries.

The first two immigrants to Missouri from my ancestral home in Germany arrived in 1832, attracted by a guidebook that touted the virtues of the young state. It took just one year for the first chain migrants to follow. Within two decades, this settlement had grown to about 150 families of the same origins. As a result of this chain migration, they built two villages six miles apart named after towns just 20 miles apart in Germany.

Although a scholar of an earlier generation characterized immigrants as “The Uprooted,” testimony from their correspondence paints a much different picture. One immigrant who arrived in Missouri in 1860 wrote home: “The visiting lasted the whole night through. . . . It was as if the Prodigal Son had returned to his father, that’s how we celebrated.” Such reunions were a common refrain in letters immigrants wrote back to the “Old Country” announcing their safe arrival.

Chain migration was almost universal, regardless which ocean migrants crossed. In the 1880s, more than 46 percent of Swedes arrived on tickets prepaid by their family members who had already made the move to the United States. There is no evidence that they were drags on the economy just because they could not afford passage. In fact, even nativists, then and now, look favorably on Scandinavians.

Concerned about the causes of migration, U.S. officials queried arriving immigrants on the eve of World War I and discovered that barely 6 percent arrived without any previous contacts. About 15 percent were joining friends, but nearly four-fifths of all arrivals (79 percent) listed family members as their destination, in contrast to only 60 to 65 percent of immigrants today.

Earlier arrivals acted as intermediaries and translators, literally and figuratively, of American culture and language. They eased the search for employment. The homogeneous neighborhoods that chain migration created were decried by nativists as ethnic ghettos, but in fact such “decompression chambers” served to mitigate culture shock and alienation. That is why my generation of scholars replaced “uprooted” with “transplanted” as the reigning paradigm of the immigrant experience.

This is also why historians are vital to the debate over immigration. Most Americans have no idea just how lenient our immigration policies were in the 19th century. Today one often hears the refrain, “I’m not racist; I only oppose illegal immigration. My ancestors all came here legally.” But for anyone of European origins, there was virtually no way to immigrate illegally before World War I unless one was an anarchist, a prostitute or the like.

Otherwise the gates were wide open. German states sent thousands of convicts and tens of thousands of welfare cases to the United States on one-way tickets, and even that was legal until 1875. Before 1906, naturalization could be attained (except by Asians) after five years of residence with simply an oath of allegiance; no test of civics or English competence was required.

Lenient as such requirements were, in the 1880s 18 states and territories went further, allowing immigrants to vote once they had obtained their “first papers”: a declaration of intent to become a citizen, available after only two years.

The wave of extreme nationalism unleashed by World War I triggered a sea change in U.S. immigration policy. Asians were banned entirely, and discriminatory quotas based on national origin cut back European immigration to a small fraction of its former volume. Once the restrictive quota laws of the 1920s clamped down, groups such as Italians and Russian Jews, who were most severely affected, quickly began to illegally immigrate.

The 1965 immigration law abolished the discriminatory quotas and put all nationalities on an even, but not necessarily equal, footing. Because of discriminatory laws that virtually banned Asian immigration for two generations, when these policies were lifted in 1965, there were few available family sponsors. So most new arrivals from Asia came on educational visas. That is why Asian immigrants are more likely than the native-born population to have college degrees. The same thing is true of immigrants from Africa, who rival Asians in their educational levels — people like Barack Obama Sr., had he opted to stay here.

Over the decades, as immigration has increased from these places of origin, there are more potential sponsors, leading to more chain migration. But the educational level of Asians and Africans in the United States has remained high.

So the argument promoted by groups like FAIR, contrasting migrants who come based on family connections with those who come based on their ability to contribute, is a false one. Not only does this mistakenly equal ability with education level, it ignores the fact that sponsoring relatives are likely to encourage relatives to join them because they have found a rewarding economic niche and want to share this opportunity with their family. But whether based on ignorance or prejudice, Trump’s crusade against chain migration is a solution to a nonexistent problem.

I do not begrudge Trump’s in-laws their immigration and citizenship based on family preference visas. They are following the old American tradition of chain migration that also brought my ancestors here. All I ask is that they refrain from (as Thomas Nast captioned his 1870 cartoon skewering Irish and fellow German immigrants agitating for Chinese exclusion) “throwing down the ladder by which they rose.”