G. K. Chesterton opened his 1924 book Eugenics and Other Evils by warning that a “blow from a hatchet can only be parried while it is in the air.” The hatchet in the air was eugenics, but the blow had already hit its target in the United States. In a Supreme Court case decided three years later, Buck v. Bell, Justice Oliver Wendell Holmes Jr. wrote an opinion upholding a recently enacted Virginia statute providing for the forced sterilization of those suffering from “idiocy, imbecility, feeble-mindedness or epilepsy”—over the protests of 17-year-old Carrie Buck, who was not so feeble-minded as to be blind to the injustice being perpetrated against her.

Allowing the state to surgically remove Buck’s Fallopian tubes, over a lone dissenting vote cast by the Court’s only Catholic, Justice Pierce Butler, Holmes wrote for the Court: “It is better for all the world if, instead of waiting to execute degenerate offspring for crime or to let them starve for their imbecility, society can prevent those who are manifestly unfit from continuing their kind.” Buck was one of 60,000 people who were forcibly sterilized in the United States in the twentieth century, as Clarence Thomas noted in his recent concurring opinion in Box v. Planned Parenthood of Indiana and Kentucky, a certiorari order that artfully tabled the question whether the state of Indiana may lawfully prohibit abortions chosen because of the sex, race or disability of the unborn child whose life is terminated. Thomas’s “dangerous idea”—as Ross Douthat recently described it—is that the sordid history of eugenics in the United States remains relevant to our ongoing constitutional disputes about abortion.

Under the Supreme Court’s Fourteenth Amendment Due Process jurisprudence, a state may not burden a fundamental right unless it has a compelling interest that it pursues by the least restrictive means. Presuming, for the sake of argument, that there is a fundamental constitutional right to abortion, does the state nonetheless have a compelling interest in preventing abortions chosen for eugenic reasons—to parry, as it were, the hatchet in the air? Addressing this question and connecting it with the categories of the Court’s Equal Protection analysis, Thomas wrote a 20-page concurrence outlining in detail the history of eugenics in the United States, with the goal of demonstrating that Indiana’s law and “laws like it promote a State’s compelling interest in preventing abortion from becoming a tool of modern-day eugenics.”

As Thomas notes, the “twentieth-century birth control movement” was intertwined with and “developed alongside the American eugenics movement.” Both were “seeking to assist the race toward the elimination of the unfit,” as Margaret Sanger put it in her 1919 essay “Birth Control and Racial Betterment.” But Sanger expressed her own doubts at the end of the essay whether either “the mating of healthy couples” or the “sterilization of certain recognized types of the unfit” alone can do much to limit reproduction among “those great masses, who through economic pressure populate the slums and there produce in their helplessness other helpless, diseased and incompetent masses, who overwhelm all that eugenics can do among those whose economic condition is better.”

Start your day with Public Discourse

Sign up and get our daily essays sent straight to your inbox.

Although Sanger did not take it, the step from this starting point to eugenic abortion is not far. Just a few years after Sanger published her essay, William Ralph Inge, a liberal Anglican eugenicist, wrote frankly in his book Outspoken Essays that the “ridiculous dogma that men are born equal is dead if not buried. The ‘sanctity of human life’ must give way to the obvious truth that a garden needs weeding.” Without the dogma of the sanctity of human life, what is to prevent the gardener in this metaphor from killing the weeds?

It was a serious question, then, after the liberalization of abortion laws in the twentieth-century, whether abortion would be put to eugenic purposes. In this light, it seemed reasonable for people to interpret Ruth Bader Ginsburg’s comment in a 2009 New York Times Magazine interview as a nod to the eugenicists’ goal of discouraging the poor, or otherwise undesirable, from reproducing. “Frankly I thought that at the time Roe was decided,” Ginsburg told Emily Bazelon, “there was concern about population growth and particularly in populations that we don’t want to have too many of. So that Roe was then going to then be set up for Medicaid funding for abortion.”

In a follow-up interview with Bazelon at Yale Law School, Ginsburg insisted that she had been quoted accurately but that it had been “vastly misinterpreted.” Perhaps, and Bazelon’s charitable spin is that Ginsburg was summarizing a view that was in the air in 1973 that she herself did not hold (although her 2014 comment in a different interview that it “makes no sense as a national policy to promote birth only among poor people” seemed to endorse both the positive and negative sides of the eugenics coin).

The same charitable interpretation is impossible to give to a letter from Ron Weddington, co-counsel from Roe v. Wade, to president-elect Bill Clinton in 1992. “Having convinced the poor that they can’t get out of poverty when they have all those extra mouths to feed,” Weddington wrote, “you will have to provide the means to prevent the extra mouths”: that is, government-provided “vasectomies, tubal ligations and abortions.” To put an even finer point on it, Weddington closed his letter by insisting emphatically, “We don’t need more poor babies.” The category of the “poor,” of course, is often a proxy for other categories, whether implicitly or explicitly.

Technology has dramatically advanced even since 1992, and, as Thomas notes, “with today’s prenatal screening tests and other technologies, abortion can easily be used to eliminate children with unwanted characteristics.” This has led, for example, to the near-elimination of children with Down Syndrome in many Western countries and widespread sex-selective abortion in Asia and in some communities in the United States. There are, additionally, wide racial disparities in abortion ratios in many American communities.

It is important to keep in mind that the eu in eugenic means simply good, as in good genes, and the people espousing it thought they were espousing something good for society and for the future. Eugenics was, and is, a progressive movement—one that rests on a vision of development, progress, and perfection. The history of the twentieth century, however, shows that the heavenly vision leads to hellish results. The eugenic search for good genes comes at the cost of human dignity and human equality, and leaves by the wayside the dogma of the sanctity of human life. Rather than warning us that eugenics can happen here, Thomas’s dissent lays out the case that it already has happened here, and the state has a compelling interest in preventing its return.