Both the arguments for slavery in the 1800s and the arguments for abortion rely on a central claim: that a human being is less than human. The dehumanization of black people relied on pseudoscientific claims that they were inferior. The dehumanization of unborn babies relies on claims that they are “just a clump of cells” or part of a woman’s body. In both cases, a growing movement of moral clarity demands that the dehumanized be granted a fundamental right long denied them: freedom and life. (Note: I am not saying abortion and slavery are the same, only that the arguments for them are similar.)

Yet the dehumanization is not the only connection between the pro-slavery arguments in 1800s America and the pro-abortion arguments today. In fact, the two movements also championed a form of “choice” that focused on the will of the master and mother over the fundamental rights of the slave and unborn. They also moved away from claims that slavery and abortion are necessary evils to claims that they are a positive good. Black pro-life activists have also condemned the targeting of black women for abortion, condemning abortion as a form of genocide.

Late last month, The New York Times‘s Amy Harmon wrote a revealing piece about the language in the abortion debate. She summarized the arguments of “abortion rights advocates” who blamed President Bill Clinton for stigmatizing the term “abortion” in the late 1990s with the “safe, legal, and rare” formulation. “Describing abortion as needing to be rare implied incorrectly, in the eyes of advocates, that there was something inherently wrong with having an abortion,” Harmon wrote.

This criticism is quite telling. Indeed, activists today launch movements called “Shout Your Abortion” and a movement telling abortion stories called “You Know Me.” Far-left “comedian” Michelle Wolf even performed a stand-up segment calling for abortion to be “on the dollar menu at McDonald’s,” in an effort to fight “abortion stigma.” Increasingly, groups like Planned Parenthood are defining abortion as “health care” or “reproductive health care.”

Yet Clinton is not responsible for “abortion stigma.” That phenomenon goes back at least 2,000 years. Early Christianity forbade the killing of an unborn baby in the womb. Even Margaret Sanger, the founder of Planned Parenthood — which is America’s largest abortion provider — condemned abortion as a “disgrace to civilization.”

The “stigma” has something to do with the unavoidable moral fact that abortion kills a living human being. Thanks to modern genetics, we know that from the moment of conception an unborn baby has unique human DNA. Science, not faith, provides the strongest arguments against abortion.

Clinton supported abortion, claiming it should be “safe, legal, and rare.” Yet modern abortion advocates celebrate the practice of killing babies. In fact, New York’s radical abortion law goes so far as to strike down protections for wanted babies who are killed when a pregnant woman is abused. In order to dehumanize the unborn, New York has ruled that killing an unborn human cannot count as “homicide.”

In fact, this dehumanization also has ugly racial roots. As Supreme Court Justice Clarence Thomas pointed out last month, the abortion movement has its roots in the eugenics movement. Margaret Sanger called for more babies for the fit and fewer for the “unfit.” Governments sterilized people who were deemed unworthy to have children, and many eugenics advocates were openly racist. Indeed, just last year billboards promoted abortion specifically for black women or in black communities — most likely not with racist intentions, but with the effect of discouraging the birth of black babies.

Yet another ugly comparison comes in the language of “choice.” Indeed, earlier today “Men for Choice” was trending on Twitter. The abortion group NARAL Pro-Choice America noted that “women don’t usually get pregnant on their own. We need [Men for Choice] to step up and speak out for safe, legal abortion access because reproductive freedom benefits us all.”

Women don’t usually get pregnant on their own. We need #MenForChoice to step up and speak out for safe, legal abortion access because reproductive freedom benefits us all. https://t.co/m5iKEDOf0o #StopTheBans — NARAL (@NARAL) June 5, 2019

This language of “choice” and “freedom” echoes the arguments Northern Democrats used before the Civil War. In the decades before the war, Southern Democrats kept pushing for more and more land to be open to slavery. The Northwest Ordinance, one of the first laws passed under the Constitution in 1789, made slavery illegal in the territories of the United States. The Founders considered slavery a necessary evil, but they wanted to prevent it from spreading into future states.

Yet in the 1800s, Southern Democrats pushed for slavery to be extended into the territories. The Missouri Compromise of 1820 drew a line at the 36°30′ parallel, allowing Missouri to enter the Union as a slave state and allowing any territories below that line to enter as slave states. This was not enough for Southern Democrats, who held a great amount of power in the federal government. In 1854, they pushed the Kansas-Nebraska Act, which opened the territories of Kansas and Nebraska to what was called “Popular Sovereignty.”

Abraham Lincoln became famous for opposing Popular Sovereignty in his debates with Sen. Stephen Douglas (D-Ill.). Under Popular Sovereignty, settlers in Kansas and Nebraska would decide — by majority vote — whether the states would be “Free States” or “Slave States.” Naturally, not a single slave got a vote.

Like the “pro-choice” and “reproductive freedom” rhetoric, this radical position allowed those with a voice to overrule the wishes of the dehumanized. In abortion, only the mother gets a “choice” — and according to Supreme Court Justice Ruth Bader Ginsburg, pregnant women who get abortions aren’t even mothers. In Popular Sovereignty, only free settlers and slave-owners got a vote. In both cases, the person with the most to lose is and was disenfranchised — in the name of freedom.

Thanks to the Kansas-Nebraska Act, bands of pro-slave and pro-free settlers engaged in skirmishes and a kind of mini-Civil War called “Bleeding Kansas.”

In 1857, the Supreme Court decision Dred Scott v. Sandford denied citizenship for black people. Like Roe v. Wade (1973), it codified a systemic denial of basic rights to an entire group of people.

Like the antebellum southerners, abortion activists are pushing for a federal acknowledgment of their position in the repeal of the Hyde Amendment, which prevents taxpayer money from directly funding elective abortions. Democrats running for the 2020 presidential nomination have endorsed repealing the Hyde Amendment, and just today former Vice President Joe Biden received a great deal of flak from NARAL and Planned Parenthood for supporting the amendment.

From the Hyde Amendment to abortion bans, attacks on abortion access must stop. We deserve a president who agrees: EVERYONE deserves access to safe, legal abortion. #BeBoldEndHyde pic.twitter.com/aOAwx6AfYw — Planned Parenthood Action (@PPact) June 5, 2019

The Northwest Ordinance and the Missouri Compromise were grand compromises allowing something immoral but restricting it, so that not all Americans were complicit in that evil. Similarly, the Hyde Amendment was designed to protect Americans from being forced to pay for something so many of them consider immoral.

Contrary to popular belief, abolitionists did not drive the Civil War, and Lincoln would have been happy to preserve the Union without ending slavery. The Southern states seceded because Lincoln opposed the expansion of slavery, and they could brook no compromise. In fact, the Southern states had been losing their stranglehold on the Federal Government, and Lincoln’s victory scared them into rebellion. Lincoln issued the Emancipation Proclamation in 1863 as a war measure. In his Second Inaugural Address, Lincoln said the Civil War was God’s just judgment on the United States for accepting slavery.

Pro-life advocates fear that the moral horror of abortion merits a similar punishment. The current rancor of abortion politics seems to have reached a fever pitch, but it is not likely to abate any time soon.

Even if Roe v. Wade is overturned, that will not outlaw abortion in the 50 states. Instead, that will allow the 50 states to make their own laws on abortion, with pro-life states outlawing it and pro-abortion states passing laws similar to New York’s law and the Illinois abortion law.

Antebellum southerners defended slavery as essential for their economy. Slavery opened up economic options for the masters and undergirded Southern society, so the argument went. Similarly, abortion advocates claim that the decision to kill an unborn baby is vital for women, to allow them to gain education, prosperity, and care for their existing children. These are real concerns, just as the southerners’ economic concerns about slavery were also real. Abolition did indeed roil the South’s economy, but later Americans judge that it was a moral victory.

Abortion also undergirds the Sexual Revolution. The unspoken truth about “pro-choice” rhetoric is that abortion activists want people to be able to have sex without consequences, both physical and emotional. Babies do not come out of nowhere. For all the talk of “forced pregnancy,” the vast majority of children are conceived through consensual sex. (Pregnancies from rape are of course a sticky issue, and Americans rightly support harsh penalties for rapists.)

The moral scourge of abortion, like the moral scourge of slavery, weighs on America’s conscience. As pro-slavery advocates argued for Popular Sovereignty, so pro-abortion advocates argue for “reproductive freedom.” As pro-slavery advocates dehumanized black people, so pro-abortion advocates dehumanize the unborn. As pro-slavery advocates became more radical, defending slavery as a positive good and expanding slavery into the territories, so pro-abortion advocates have become more radical, shouting their abortions, demanding an end to the Hyde Amendment, and claiming that any restrictions on abortion make America into a misogynistic theocracy.

In both cases, activists cannot silence the conscience, no matter how loud and radical they become.

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