The Abortion Wars
Ours is not the first abortion war. Two previous periods saw protracted contests over whether abortion would be accepted or proscribed.
The first was in the early centuries of Christianity, when faith spread within a Greco-Roman culture that considered abortion (and infanticide) routine. The second was in America during the mid-nineteenth century when abortions became widespread, freely advertised in virtually every newspaper.
The third abortion war is now approximately  years old and shows no sign of peace. Living in a battle zone, we can easily focus on the tactics of the moment and forget the wider context. The danger in forgetting is that when the situation suddenly shifts, as it did in 1973 with Roe v. Wade and in 1989's Webster decision, we get thrown off. Suddenly the tactics we had honed become irrelevant, and the goals we had set are outdated.
The first war
People commonly suppose that abortion is an invention of modern, technological medicine. In fact, it was well known in Greco-Roman society. Plato's Republic made abortion or infanticide obligatory if the mother was over 40. In Aristotle's ideal society, abortion would be compulsory for families that exceeded a certain size.
Aristotle also made a distinction that would develop a life of its own: the "formed" versus the "unformed" fetus. Aristotle believed that human life was present in the fetus when distinct organs were formed, 40 days after conception for males and 90 for females. This was a metaphysical, not a moral, distinction; Aristotle would abort both "formed" and "unformed" fetuses. But some Christians—Augustine of Hippo and Thomas Aquinas in particular—would later adopt his distinction. It survived in various forms right down to the arbitrary trimesters of Roe v. Wade.
Both Plato and Aristotle believed that a child had life long before birth; it was just that the welfare of society and family were more important to them than the rights of a child. The Roman empire made the same assessment while adopting the Stoic belief that life begins only at birth. Abortion was common. As Michael Gorman puts it in Abortion and the Early Church, the Roman empire was paradoxically "profamily but not fundamentally antiabortion. That the fetus is not a person was fundamental to Roman law. Even when born, the child was valued primarily not for itself but for its usefulness to the father, the family and especially the state."
Many Romans opposed abortion, but Gorman says, "Pagan antiabortion statements are consistently mindful of the welfare and rights of the state, the father, the family and even occasionally the woman, but never those of the fetus. … Christians discarded all pagan definitions of the fetus as merely part of the mother's body. To Christians, the fetus was an independent living being."
From the first, Christians were outspokenly opposed to abortion on the basis of the child's right to life. The Didache, an early second-century document summarizing Christian belief and practice, declares, "Thou shalt not murder a child by abortion/destruction." Clement of Alexandria, Tertullian, Jerome, Basil the Great, Ambrose—all pronounced against abortion. Tertullian wrote eloquently in his Apology, aimed at non-Christians: "To hinder a birth is merely a speedier man-killing; nor does it matter whether you take away a life that is born, or destroy one that is coming to the birth. That is a man which is going to be one; you have the fruit already in the seed."
That is how Western society came to be antiabortion. Although the church's antiabortion arguments were consistent and insightful, the change in society was due more to the fact that Christians won the empire to their faith. Not long after Constantine legalized Christianity, it was made illegal for a father to kill his children. Roman abortion laws were never changed, but as the institutional church's role grew more important, ecclesiastical penalties for abortion—their severity was between those for manslaughter and murder—became meaningful legislation for the entire society.