The antiabortion movement has almost won its holy grail. The leaked draft opinion by Justice Samuel A. Alito Jr. reported by Politico on Monday indicates that the Supreme Court is ready is overturn nearly 50 years of precedent and find that there is no constitutional right to an abortion.

Unless a justice in the majority changes his or her mind before the court finalizes the decision, the ruling would signal that the antiabortion movement has changed the tides of history. This success is the product of powerful conservative coalitions but, crucially, the antiabortion movement has successfully co-opted and reworked leftist rhetoric about rights.

As state legislatures in the late 1960s began to liberalize their abortion laws, the emerging antiabortion movement faced serious cultural and political obstacles. Many Americans were skeptical of religious movements imposing their will on others. They also confronted a rising feminist movement arguing that women were an oppressed class. Women’s inability to control their reproduction meant they could not be full citizens.

Recognizing the power of these claims, the nascent antiabortion movement rejected the open crusade to regulate women’s sexuality embraced by the anti-birth-control movement of the early 1960s. While anti-birth-control forces asserted that states should punish promiscuity and the women who enjoyed it, antiabortion activists understood that this explicit sexism and religiosity would no longer sell.

But the new language pioneered by the ascendant rights movements of the decade — especially the civil rights movement — offered a solution to this problem. These movements made Americans familiar with claims about the need for new laws to protect the rights of minority groups. As historian Sara Dubow and others have shown, antiabortion activists adopted this language, developing secular arguments centered on the civil rights of fetuses.

This formulation allowed them, for example, to compare abortion to slavery and the Holocaust. All three devalued or eradicated human life, they claimed. But abortion was the worst of the three, according to antiabortion activists. The growing number of abortions would eventually outpace the number of people murdered during the Holocaust or killed in the Civil War. It was also worse because the fetus was the ultimate innocent victim. One activist wrote to his Utah legislator in 1973: “As far as I [am] concerned [Roe v. Wade] is far more tragic than anything Hitler ever did, at least his victims weren’t completely helpless and could fight to a degree for themselves.”