Alabama, Georgia, and Missouri are currently passing restrictive abortion laws with the clear aim of forcing the Supreme Court to rule again on the constitutionality of Roe v. Wade. The conservative efforts to pass these laws and to nominate conservative judges is part of a grand bargain between religious, often evangelical, pro-life voters and political conservatism. It’s an alliance that helped propel Donald Trump to the presidency.

Critics of these laws, and of the anti-abortion movement in general, often charge that Republicans aren’t pro-life but rather pro-birth. Where, they ask, is the support for pregnant mothers? For children and families?

In its early days, the pro-life movement opposed abortion, but also aimed to address what they saw as its economic causes. But abortion legalization led pro-lifers to embrace the American right even though limited-government types aren’t a natural ally.

There’s some irony in southern states becoming the battlegrounds for a Supreme Court challenge to Roe v. Wade, and in evangelicals being the demographic most associated with pro-life politics. For much of the twentieth century, opposition to abortion was a Catholic issue; the Southern Baptist Convention did not pass a resolution about abortion until 1971.

In the 1960s, doctors spearheaded an effort to reform abortion law to allow “therapeutic” abortions in cases where pregnancy threatened maternal health (in practice, medical providers construed this broadly). Abortion law reform advocates pitched their arguments as harm reduction and bringing the law in line with practice. Sixteen states passed therapeutic abortion laws in the late 1960s.

The Bible Belt was more open to this liberalization than much of the rest of the country, especially states where the Catholic Church had sway. In 1967, North Carolina liberalized its laws without much backlash. Georgia followed suit in 1968. During this period, Alabama, which allowed abortions in cases of woman’s health, provided greater access to abortion than New York or New England.

Crucially, these laws allowed “therapeutic” rather than “elective” abortions. Although doctors gave a lot of latitude to medical necessity, these were, in theory, abortions with a medical reason and regulated by the medical profession.

The Catholic voters who opposed abortion access were also a key part of the Democratic New Deal coalition. Although conservative on religious, gender, and reproductive issues, Catholics were, by and large, in favor of generous governmental programs. Catholic social teaching from the Vatican through the American Bishops Conference and down to local parishes supported workers’ rights and welfare. Most Catholic voters opposed the strongly Protestant and business-oriented Republican Party.

If the Bible Belt was once on the forefront of abortion liberalization, conservatives were also more equivocal about abortion than you might expect. Mostly it wasn’t on their radar or they saw it as a Catholic issue. In 1966, America’s most prominent right-wing columnist, William F. Buckley, a Catholic, suggested his church should dial down opposition to abortion law reform in cases of “maternal health, rape, defect in fetus” on religious freedom grounds. Much of the Republican Party, including conservative senators John Tower and Barry Goldwater, were staunchly pro-choice. A 1969 poll found Republicans led Democrats by 10 percent in their support for legalized abortion in the first trimester (46 percent to 35 percent).

This soft conservative support for abortion makes some sense. The conservative movement had a strong anti-welfare view and generalized libertarian tone that could easily treat abortion as private, personal choice where sectarian religious views had no relevance.

Columnist James J. Kilpatrick put this view bluntly: abortion should be available through Medicaid or else women “will resort to the brutal services of back-alley butchers” or “coat hangers and button hooks.” If not for abortion, unwed mothers would “carry their infants to full term, be delivered at public expense, and dump their progeny on the taxpayers for life.” (In this warning, the formerly segregationist Kilpatrick echoed Alabama governor George Wallace’s remark that single black women were “breeding children as a cash crop.”)

In 1970, both Hawaii and then New York legalized elective abortion, effectively legalizing abortion in the United States for those who could afford to travel.

At first, conservatives had conflicting responses. In National Review, a major conservative magazine, the high-profile Republican and Catholic convert Clare Booth Luce warned that moderate laws could easily become permissive. But Luce concluded abortion was a cultural issue, not a legal one. How could Catholics legislate against five hundred thousand illegal abortions? What was needed was an end to the “abortion mentality,” not an unworkable law. Shortly after, the magazine published another article calling for a culturally aware but total fight against elective abortion. The author, Will Herberg, asserted fetal right to life against women’s rights to control their body.

Conservative elites like Luce and Buckley were willing to accept a modus vivendi based on arguably fictive therapeutic abortion and the demands of many American women. Pro-life activists, many of whom were Catholic, found this stance deeply disappointing.

The legalization of elective abortion caused many conservatives to clarify their positions. Elective abortions shocked conservatives for several reasons. First, they were alarmed by the number of legally performed abortions, which jumped dramatically from 193,491 in 1970 to 485,816 in 1971 (these numbers do not include abortions performed in California, New Hampshire, or Maryland which are not reported to the CDC). Around this time, too, pro-life activists pioneered the aggressive use of fetal images and graphic descriptions of (now no longer used) abortion methods to shock voters and legislators into opposing further legalization.

Second, conservatives saw the concept of elective abortions as antithetical to traditional sexual mores that prescribe female chastity and motherhood. Meanwhile, feminists took increasing ownership of abortion as a right and a necessary requirement for equality.

The turning point in the relationship between pro-life activists and right-wingers was Roe v. Wade. The pro-life fight against the Court decision led conservatives and pro-lifers into a long embrace.

In Roe v. Wade, the Supreme Court found the right to abortion in the Constitution. In part, the Court sought to depoliticize the contentious issue by settling it once and for all. In establishing abortion as a right, the Court rewrote law in forty-five states. In Alabama, the legislature kept their (once liberal, now restrictive) law that allowed abortion in cases of maternal health on the books until the Court struck it down in 1975.

Many movement conservatives were shocked. Buckley called Roe “outrageous,” the “Dred Scott of the twentieth century.” Conservative evangelical Christians, meanwhile, turned against abortion in a big way. The evangelical thinker Francis Schaeffer led a shift in evangelical views against abortion in both the pulpits and pews, connecting abortion to the destruction of human life, female sexual promiscuity, and the decline of Western Civilization. Opposing abortion became a conservative Christian issue, not just a Catholic one.

Since Roe v. Wade made access to abortion a constitutional right, pro-life activists realized extraordinary measures were necessary if they wanted to outlaw it. One strategy was to make an end run around Roe. This meant constitutional amendments either to establish a right to life at conception or to send the issue back to the states. When a constitutional amendment proved impossible, pro-lifers began pushing for Supreme Court justices committed to overturning Roe v. Wade.

A second strategy was to make smaller legislative efforts to reduce access to abortion with the aim of effectively outlawing it.

The pro-life movement pursued both approaches and each pushed them toward the Republican Party.

Because of the growing strength of the liberal wing in their party, Democratic presidential candidates after 1972 were unwilling or unable to commit to pro-life causes like the Human Life Amendment or anti-Roe judges. Republicans, on the other hand, saw an opening.

Richard Nixon used the right-to-life cause as part of his “social issue” effort to peel white working- and middle-class votes from the Democratic coalition. His successor, Gerald Ford, was a classic small government Republican who favored a “states’ rights amendment” and legal therapeutic abortion (First Lady Betty Ford, however, was a major abortion rights advocate). Finally, Ronald Reagan solidified anti-abortion votes for the GOP with a clear, although often ineffective, effort to use the Justice Department to oppose Roe.

For single issue anti-abortion voters, for whom the moral weight of abortion is tremendous, the Republican Party became their only possible home. This identification with the GOP has only become stronger as the Democratic Party has, at least since 1992, insisted that reproductive rights are central to their platform.

And as historian Jennifer Donnally shows, pro-life activists sought to cut federal funding for abortions for women on public assistance. This strategy, she argues, dovetailed with the conservative movement’s anti-government tax-payer revolution ethos.

We might add that the legal attack on Roe derived from the conservative view that liberal judges over-interpreted the Constitution to “find” a right to abortion in the “penumbra” of the Constitution through the so-called right to privacy. Conservatives have a long history of grievances with liberal justices finding rights and powers in the Supreme Court. Conservative distrust of the Court dates back to the New Deal but intensified as a result of Brown v. Board of Education and the “Rights Revolution” of the 1960s and 1970s.

Aligning with conservative Republicans was an straightforward transition for evangelical voters who, according to historian Daniel K. Williams, long identified with Republican politics. But for Catholic former Democratic voters, embracing the small government Republican Party was a denial of Catholic and, as Williams argues, pre-Roe pro-life politics that prohibited abortions but also voted for welfare programs to reduce the need for them.

In recent years, some Christian writers like Elizabeth Bruenig and the late Rachel Held Evans have broken with the pro-life movement’s new orthodoxy and revived parts of this older pro-life approach by promoting government support for women and families, including subsidies, maternity leave, and childcare, to reduce economic pressure on women and families.

From this perspective, the conservative movements explicit libertarian commitments, its emphasis on small government and anti-welfare rhetoric have made it a fair-weather ally for pro-life voters. Yet, the pro-life movement’s rigid political emphasis on criminalizing abortion and overturning Roe means that, despite this tension, most pro-lifers will be Republicans for the foreseeable future.

Joshua Tait is a columnist for Arc Digital. Read more of his work and follow him on Twitter.