When the Supreme Court ruled that women had, because of the constitutional right to privacy, to be guaranteed access to safe and legal abortion providers, it wasn't a huge issue for the conservative American Evangelical churches. Their leaders had taken the position for years that the fetus was an "undeveloped human" and didn't therefore have rights.
That's not the same for the Roman Catholic Church, where as early as the 1 Century in the Didache there is an explicit prohibition against abortion. But American Evangelicals weren't there in the 1970's. And wouldn't become unanimous in their opposition and political activism against abortion rights until latter part of the next decade.
Jonathan Dudley, in recent book that chronicles this shift even begins by quoting a conservative seminary professor, writing in a Billy Graham sponsored publication, who argues from the Torah that killing a fetus is different than killing a human.
Dudley goes on in his book entitled Broken Words: The Abuse of Science and Faith in American Politics to detail how strongly this change in sentiment to uncompromising opposition to abortion rights shifted the landscape of the American Evangelical politics.
"By the mid-1980s, the evangelical right was so successful with this strategy that the popular evangelical community would no longer tolerate any alternative position. Hence, the outrage over a book titled Brave New People published by InterVarsity Press in 1984. In addition to discussing a number of new biotechnologies, including genetic engineering and in vitro fertilization, the author, an evangelical professor living in New Zealand, also devoted a chapter to abortion. His position was similar to that of most evangelicals 15 years prior. Although he did not believe the fetus was a full-fledged person from conception, he did believe that because it was a potential person, it should be treated with respect. Abortion was only permissible to protect the health and well-being of the mother, to preclude a severely deformed child, and in a few other hard cases, such as rape and incest.
Although this would have been an unremarkable book in 1970, the popular evangelical community was outraged. Evangelical magazines and popular leaders across the country decried the book and its author, and evangelicals picketed outside the publisher’s office and urged booksellers to boycott the publisher. One writer called it a “monstrous book.” … The popular response to the book — despite its endorsements from Carl F.H. Henry, the first editor of Christianity Today, and Lew Smedes, an evangelical professor of ethics at Fuller Theological Seminary — was so overwhelmingly hostile that the book became the first ever withdrawn by InterVarsity Press over the course of nearly half a century in business.
The book was republished a year later by Eerdmans Press. In a preface, the author noted, “The heresy of which I appear to be guilty is that I cannot state categorically that human/personal life commences at day one of gestation. This, it seems, is being made a basic affirmation of evangelicalism, from which there can be no deviation. … No longer is it sufficient to hold classic evangelical affirmations on the nature of biblical revelation, the person and work of Christ, or justification by faith alone. In order to be labeled an evangelical, it is now essential to hold a particular view of the status of the embryo and fetus.”"
Fred Clark writes about this and more. Clark points out that most of us have forgotten that this shift took place. Did you know about it? (I sure didn't.)