On Tuesday, the Supreme Court refused to take up the issue of Indiana’s ban on abortion specifically for the sex, race, or disability of the baby to be killed. Justice Clarence Thomas wrote a powerful opinion revealing the connections between the racist eugenics movement and the abortion movement. He warned that if Planned Parenthood is able to get sex-selective, race-specific, and disability-targeted abortions codified as a woman’s right under the Constitution, that would enshrine a horrific movement rightly left in the past.

“Enshrining a constitutional right to an abortion based solely on the race, sex, or disability of an unborn child, as Planned Parenthood advocates, would constitutionalize the views of the 20th-century eugenics movement,” Thomas warned. “In other contexts, the Court has been zealous in vindicating the rights of people even potentially subjected to race, sex, and disability discrimination.”

Yet abortion activists argue that Roe v. Wade (1973) was correct in ruling that abortion is a fundamental right for women. They claim that this right should override any other concerns, even race, sex, and disability discrimination applied to an unborn baby.

Thomas condemned this abortion argument, showing how it echoes the disgusting eugenics movement. He argued that the Indiana law “and other laws like it promote a State’s compelling interest in preventing abortion from becoming a tool of modern-day eugenics.”

The ties between abortion and eugenics run deep into history. “The foundations for legalizing abortion in America were laid during the early 20th-century birth-control movement,” Thomas argued. “That movement developed alongside the American eugenics movement. And significantly, Planned Parenthood founder Margaret Sanger recognized the eugenic potential of her cause. She emphasized and embraced the notion that birth control ‘opens the way to the eugenist.'”

“As a means of reducing the ‘ever increasing, unceasingly spawning class of human beings who never should have been born at all,’ Sanger argued that ‘Birth Control . . . is really the greatest and most truly eugenic method’ of ‘human generation.'” Yet Thomas claimed that “Sanger’s arguments about the eugenic value of birth control in securing ‘the elimination of the unfit,’ … apply with even greater force to abortion, making it significantly more effective as a tool of eugenics. Whereas Sanger believed that birth control could prevent ‘unfit’ people from reproducing, abortion can prevent them from being born in the first place.”

While Sanger condemned abortion as a “disgrace to civilization,” many eugenicists supported legalizing abortion, and many abortion advocates endorsed using abortion for eugenic reasons, including most notably future Planned Parenthood President Alan Guttmacher. “Technological advances have only heightened the eugenic potential for abortion, as abortion can now be used to eliminate children with unwanted characteristics, such as a particular sex or disability.”

Thomas laid out a brief history of the eugenics movement. “As a social theory, eugenics is rooted in social Darwinism—i.e., the application of the ‘survival of the fittest’ principle to human society.” He cited Francis Galton, the British statistician who coined the term in 1883. “Galton argued that by promoting reproduction between people with desirable qualities and inhibiting reproduction of the unfit, man could improve society by ‘do[ing] providently, quickly, and kindly’ ‘[w]hat Nature does blindly, slowly, and ruthlessly.'”

By the 1920s, eugenics leaders held prominent positions at Harvard, Stanford, and Yale, and eugenics was taught at 376 universities and colleges. “Many eugenicists believed that the distinction between the fit and the unfit could be drawn along racial lines, a distinction they justified by pointing to anecdotal and statistical evidence of disparities between the races.”

In addition to race, eugenics proponents would target people on the basis of claims that they are “feeble-minded,” “insane,” “criminalistic,” “de-formed,” “crippled,” “epileptic,” “inebriated,” “diseased,” “blind,” “deaf,” and “dependent (including orphans and paupers).” Many states passed laws prohibiting marriages between “unfit” individuals, but forced sterilization was the preferred approach.

The Supreme Court defended forced sterilization in Buck v. Bell (1927). Thomas quoted Supreme Court Justice Oliver Wendell Holmes Jr., who wrote, “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. The principle that sustains compulsory vaccination is broad enough to cover cutting the Fallopian tubes. Three generations of imbeciles are enough.”

By 1931, 28 of the 48 states had adopted eugenic sterilization laws. More than 60,000 people were involuntarily sterilized between 1907 and 1983. Support for the eugenics movement waned after World War II and the discovery of the Holocaust.

Margaret Sanger herself not only encouraged birth control to stop the reproduction of “the majority of wage workers” who would lead to “the contributing of morons, feeble-minded, insane and various criminal types to the already tremendous social burden constituted by these unfit,” but also to stop the growth of the black community.

“Sanger herself campaigned for birth control in black communities. In 1930, she opened a birth-control clinic in Harlem,” Thomas noted.

“Noting that blacks were ‘notoriously underprivileged and handicapped to a large measure by a “caste” system,’ she argued in a fundraising letter that ‘birth control knowledge brought to this group, is the most direct, constructive aid that can be given them to improve their immediate situation.'”

Thomas also cited a report called “Birth Control and the Negro” in which Sanger and her coauthors “identified blacks as ‘the great problem of the South,’ the group with ‘the greatest economic, health, and social problems’—and developed a birth-control program geared toward this population. She later emphasized that black ministers should be involved in the program, noting, ‘We do not want word to go out that we want to exterminate the Negro population, and the minister is the man who can straighten out that idea if it ever occurs to any of their more rebellious members.'”

Though Sanger opposed abortion, her successor Guttmacher wrote that the question of legalizing abortion must be “separated from emotional, moral and religious concepts” and “must have as its focus normal, healthy infants born into homes people with parents who have healthy bodies and minds.”

Decades ago, leaders in the black community knew that eugenics, birth control, and abortion targeted them. “Some black groups saw ‘family planning’ as a euphemism for ‘race genocide’ and believed that ‘black people [were] taking the brunt of the ‘planning’ under Planned Parenthood’s ‘ghetto approach’ to distributing its services,” he wrote. In 1968, “The Pittsburgh branch of the National Association for the Advancement of Colored People criticized family planners as bent on trying to keep the Negro birth rate as low as possible.”

Abortion has already proved effective at achieving many eugenics goals, Thomas argued. “In Iceland, the abortion rate for children diagnosed with Down syndrome in utero approaches 100%… In Asia, widespread sex-selective abortions have led to as many as 160 million ‘missing’ women—more than the entire female population of the United States. … [S]ex-selective abortions of girls are common among certain populations in the United States as well.”

Eighty years after Sanger’s “Negro Project,” black babies are far more likely to be aborted than white babies, the Supreme Court justice noted. “The reported nationwide abortion ratio— the number of abortions per 1,000 live births—among black women is nearly 3.5 times the ratio for white women. And there are areas of New York City in which black children are more likely to be aborted than they are to be born alive—and are up to eight times more likely to be aborted than white children in the same area.”

Citing the popular 2009 economics book Freakonomics, Thomas noted that “Some believe that the United States is already experiencing the eugenic effects of abortion.” He quoted Steven Levitt, “Roe v. Wade help[ed] trigger, a generation later, the greatest crime drop in recorded history.”

“It was against this background that Indiana’s Legislature, on the 100th anniversary of its 1907 sterilization law, adopted a concurrent resolution formally ‘express[ing] its regret over Indiana’s role in the eugenics movement in this country and the injustices done under eugenic laws,'” Thomas wrote. “Recognizing that laws implementing eugenic goals ‘targeted the most vulnerable among us, including the poor and racial minorities… for the claimed purpose of public health and the good of the people,’ the General Assembly ‘urge[d] the citizens of Indiana to become familiar with the history of the eugenics movement’ and ‘repudiate the many laws passed in the name of eugenics and reject any such laws in the future.'”

This Supreme Court justice seems to have taken this project upon himself.

Following this condemnation of eugenics, the Indiana legislature passed the Sex-Selective and Disability Abortion Ban that the Supreme Court considered. “Respondent Planned Parenthood promptly filed a lawsuit to block the law from going into effect, arguing that the Constitution categorically protects a woman’s right to abort her child based solely on the child’s race, sex, or disability.”

This argument effectively amounts to a claim that the Constitution protects eugenics.

Thomas agreed that the Court was right to avoid taking up this issue now, but he warned that it will not be able to delay forever.

“Although the Court declines to wade into these issues today, we cannot avoid them forever,” he warned. “Having created the constitutional right to an abortion, this Court is dutybound to address its scope.”

Is abortion the one place in which discrimination on the basis of race, sex, and disability is acceptable under the Constitution? Planned Parenthood seems to think so, and in arguing this, it is following former president Guttmacher. Americans need to condemn the eugenics movement and its disgusting modern defender — Planned Parenthood.

Follow Tyler O’Neil, the author of this article, on Twitter at @Tyler2ONeil.