In its challenge to the “contraception mandate” of the Affordable Care Act, Hobby Lobby claims that certain forms of birth control—Plan B, “ella,” and IUDs—induce abortion and therefore go against the owners’ religious beliefs. The government’s response is that none of these contraceptives ends a pregnancy. Rather, they prevent implantation in the uterine lining.

The rejoinder, from supporters of Hobby Lobby and Conestoga Wood Specialties, is that this doesn’t matter. “Although the government has made statements that terminating a fertilized embryo before it implants in the uterus is not an abortion,” writes Bart Stupak and Democrats for Life in an amicus brief filed in support of Hobby Lobby, “the relevant matter for claim of conscience … is plaintiffs’ belief that a distinct human life begins at fertilization. It is no salve … to be told that the government defines abortion differently.”

There’s no doubt that this belief is sincere. But what’s fascinating is the extent to which, for conservative evangelicals, it’s new. So new, in fact, that when Hobby Lobby’s president, Steve Green, was a child in the 1960s, it was the minority view among American evangelical Protestants.

In his book Broken Words: The Abuse of Science and Faith in American Politics, Jonathan Dudley notes that most evangelicals held far more liberal views at the time. “God does not regard the fetus as a soul no matter how far gestation has progressed,” wrote professor Bruce Waltke of Dallas Theological Seminary in a 1968 issue of Christianity Today on contraception and abortion, edited by Harold Lindsell, a then-famous champion of biblical “inerrancy.” His argument rested on the Hebrew Bible, “[A]ccording to Exodus 21:22–24, the destruction of the fetus is not a capital offense. … Clearly, then, in contrast to the mother, the fetus is not reckoned as a soul.”

This position was reaffirmed at a symposium sponsored by Christianity Today and the Christian Medical & Dental Associations, where participants agreed to disagree over the “sinfulness” of an “induced abortion,” but agreed about “the necessity of it and permissibility for it under certain circumstances,” namely, rape and incest. The document produced by the conference, “A Protestant Affirmation on the Control of Human Reproduction,” said, “The prevention of conception is not in itself forbidden or sinful providing the reasons for it are in harmony with the total revelation of God for married life” and that the “method of preventing pregnancy is not so much a religious as a scientific and medical question to be determined in consultation with one’s physician.”

Three years after the symposium, the conservative Southern Baptist Convention endorsed this view, with a call for “Southern Baptists to work for legislation that will allow the possibility of abortion under such conditions as rape, incest, clear evidence of severe fetal deformity, and carefully ascertained evidence of the likelihood of damage to the emotional, mental, and physical health of the mother.”

By 1982, however, the SBC—along with most American evangelicals—had switched gears entirely. During that year’s convention, delegates held that “human life begins at conception” and that they would work for “appropriate” legislation or a constitutional amendment to “prohibit abortions except to save the physical life of the mother.”

What happened to cause this sea change in attitudes toward fetal life and abortion among evangelicals? In short, politics, and in particular, the successful coalition-building of Jerry Falwell, Paul Weyrich, and other Christian conservatives in the wake of Roe v. Wade. Conservative Catholics were quick to mobilize against the court’s ruling, but many Protestant evangelicals were relatively apathetic. At that point, “culture war” issues such as abortion, feminism, and homosexuality weren’t on their radar (hence Jimmy Carter’s successful appeal to them in the 1976 presidential election).

It took the organizational might of Falwell and his “Moral Majority”—as well as evangelical anti-abortion figures such as Francis Schaeffer—to galvanize evangelicals around other “culture war” issues such as feminism, homosexuality, and school prayer. This in turn led to alliances with largely Catholic organizations like the National Right to Life Committee.

Belief tends to follow behavior, and working in political alliance with Catholics—a significant shift from earlier periods of evangelical political activism—led conservative evangelicals to adopt “pro-life” positions on abortion. Likewise, there was a shift in evangelical media—via books, magazines, radio, and television—toward anti-abortion beliefs. In 1980 Falwell declared, “The Bible clearly states life begins at conception.” Four years later, notes Dudley, InterVarsity Press—an evangelical imprint—was forced to withdraw a book that restated the earlier consensus around abortion.

Again, the clearest picture of this comes by way of the Southern Baptist Convention, which resolved in favor of limited abortion rights through much of the 1970s, but then made an abrupt shift in 1979 and 1980. By the late 1980s, the SBC had all but erased its previous history of abortion acceptance. To wit, at the beginning of its endorsement of the 1987 “Danforth amendment,” the SBC held that “Southern Baptists have traditionally opposed abortion.”

At the moment, few evangelicals have joined conservative and traditional Catholics in opposing birth control. It has been an extreme position for evangelicals, limited to the far right wing of the movement. Indeed, in a 2009 poll by the National Association of Evangelicals, 90 percent of respondents said that they approve of contraception. But the fight against the Obamacare contraception mandate has begun to transform the landscape of evangelical belief about hormonal birth control. Concerns over potential “abortifacients” like Plan B have led to concerns over the “pill” itself, and evangelical leaders like Albert Mohler have warned their followers against the “contraceptive mentality,” and encouraged them to “look closely at the Catholic moral argument” for guidance.

Ask most (white) evangelicals about the morality of abortion these days, and you’re certain to hear about its absolute immorality in most, if not all, circumstances. But this is a recent innovation in the history of evangelical belief, a product of political forces as well as new theological insight. That’s not to say that it’s illegitimate, only that—like more liberal evangelicals and mainline Protestants—conservatives aren’t immune to the winds of the world around them. Their beliefs, like those of the people around them, change with time and circumstance.

If the Hobby Lobby fight over the contraception mandate is any indication, we’re seeing history repeat itself. There’s a good chance that, in 10 years, conservative evangelicals will hail their opposition to birth control as a “timeless biblical truth,” the traditional view of “traditional” Christians.