“How about allowing people to come through an open border, 13,000 of which were murderers. Many of them murdered far more than one person, and they’re now happily living in the United States. You know, now a murderer, I believe this, it’s in their genes. And we’ve got a lot of bad genes in our country right now.”
“The character of our future civilization will be modified by the ‘blood’ or the natural hereditary qualities which the sexually fertile immigrant brings to our shores. This modification will be manifest to that degree to which the descendants of immigrants constitute our future citizenry. We should therefore make the possession of desirable natural qualities one of the conditions for the admission of sexually fertile immigrants.”
Two quotes, uttered by two men, separated by a century. Yet both aimed their words against immigrants. And both relied on the xenophobic logic and pseudoscientific understandings of heredity that define eugenics.
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Eugenics was debunked as both biologically unsound and morally repugnant decades ago, but Donald Trump has repackaged its key lies to appeal to 21st-century American anxieties. In his worldview, there are hereditary haves and have-nots. Biology is used, not to draw attention to what all humans have in common, but instead to manufacture artificial divisions. It is a tool of dehumanization, meant to reinforce the notion that some people are inherently broken, inherently evil, inherently other. It is a weapon of the powerful, employed to convey the idea that there is a natural ordering of humans.
Yet, in spouting their misguided ideology, Trump and many of his MAGA acolytes show that they don’t know anything about American history or biology. If they did, they would know that the divisive rhetoric they shout today is identical to what eugenicists, politicians and the like used to target many of their own ancestors a century ago—people from Germany, Ireland, Poland and Italy, among others. When we do not know, or willfully ignore history, we are doomed to repeat it.
In the late 19th and early 20th centuries, an influx of immigrants from Europe and Asia raised anxieties among American citizens about the nation’s demographic shifts. Foreigners, the worry went, weren’t assimilating; they were bringing crime and poverty. The biggest concern, according to eugenicists, was that these antisocial tendencies were inborn—that genes for crime and poverty were being smuggled into the country in the blood of immigrants. Eugenicists divided the world into the “fit” and the “unfit” and believed a nation flourished only when it incentivized more breeding among people thought to have genes for leadership and honesty, and less breeding among people who had genes for low intelligence (“feeblemindedness” in eugenics parlance) and depravity.
Harry Laughlin, the most prominent American eugenicist of the era, made the biological case for putting eugenic principles into practice. One method involved sterilizing people deemed unfit who were already living in the U.S.; over 60,000 Americans were sterilized during the 20th century under the eugenic idea that the world would be a better place if they could not reproduce. But sterilization wasn’t the only method available to eugenicists. Immigration restriction, Laughlin argued, was another way for keeping the unfit out of the U.S, entirely. The second quote above is just one example of his extensive 1920 testimony to the Committee on Immigration and Naturalization, where he made the case for curtailing immigration from Asia and parts of Europe before Congress.
By one measure, Laughlin’s testimony was a profound success. Four years after his testimony, the eugenically inspired Immigration Act of 1924 passed with overwhelming bipartisan support in both the House and the Senate and was signed into law by President Calvin Coolidge. Also known as the Johnson-Reed Act, this legislation—of which the current year marks a grim centennial—set up a restrictive quota system, indiscriminately targeting for exclusion entire continental regions and preventing hundreds of thousands of people from making a home in the U.S. It fueled nativistic and racist ideas about who did and did not belong in America.
By another measure, though, Laughlin’s eugenic advocacy was a historic debacle. A rising tide of anti-eugenic scientists took issue with the biological myths undergirding his vision. Genetic research on plants, fruit flies, livestock and humans revealed more and more about how chromosomes and genes worked. The human genome was found to be far more complex than eugenicists anticipated. There simply were no genes for crime or poverty, let alone leadership or honesty. What’s more, social scientists simultaneously uncovered the ways that things like crime and poverty were caused by features of the environment: poor economic opportunities, food and housing insecurity, racial and ethnic discrimination that impeded employment. “Unfit” was just a derogatory derision of people who looked, talked, prayed and ate differently, dressed up with a concocted sheen of scientific legitimacy.
Geneticists have known all this for years. And yet Donald Trump talks as if biology hasn’t learned anything since Laughlin testified before Congress over 100 years ago.
“We’ve got a lot of bad genes in our country right now,” is just the latest in a pattern of eugenic comments the former president has espoused for years. In December 2023, at a New Hampshire campaign stop, he warned that undocumented immigrants were “poisoning the blood of our country.” Four years ago he told a lily-white crowd of Minnesotans, “You have good genes, you know that, right? You have good genes. A lot of it is about the genes, isn’t it, don’t you believe?”
He has been spouting this nonsense for decades. In 2007 Larry King was a recipient of Trump’s hereditary lesson. In touting his work for the how-to company the Learning Annex on King’s show, Trump said about talent and business success: “But there is something. You know, the racehorse theory, there is something to the genes. And I mean, when I say something, I mean a lot.” And go all the way back to 1998, when he told Oprah Winfrey that, to achieve financial success, “You have to be born lucky in the sense that you have the right genes.” His bottom line was that achievement or failure follows entirely from that innate aptitude.
Today immigrants from Venezuela, Haiti, Guatemala and Honduras have replaced earlier fears of those coming from Ireland, Italy and Poland. Murder genes stand in for “feeblemindedness” genes. A plan to forcibly deport millions of people living in the U.S. ratchets up Laughlin’s goal of keeping them out. Modern biology tells us immigrants entering the U.S. today are not fundamentally different at the genomic level from citizens already living in the country. They harbor no genes for criminality or poverty. They are no more or less innately “fit” than anybody else.
Laughlin’s brand of eugenics scarred the nation for generations. It provided a facade of scientific cover for intolerance, distrust, discrimination and isolationism. It wreaked economic and employment havoc on the very industries it purported to protect. It dehumanized others in the name of biology. It carved up the world between those who have the right and wrong “blood”—racist code for bad genes.
America, a land of immigrants and with many diverse groups, cannot afford the price of social division and violence a president who spouts racism based on false science brings. Trump is now using disproven eugenic theories to stir racial hatred. Eugenics was never great, and we cannot pretend that it can be made great again.
This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.