The Introduction argues that the terms of the American abortion debate have changed in ways we have mostly missed. When forced to give up on a constitutional amendment banning abortion, pro-lifers sought to control the Supreme Court and reverse Roe. As part of this mission, abortion foes promoted restrictions that would hollow out abortion rights and set up test cases for the Court. But these laws did not obviously advance a right to life since they did not criminalize any abortions. To defend them, abortion foes instead detailed the benefits of specific restrictions – and the costs of abortion itself. Over time, abortion-rights supporters had to identify concrete benefits of abortion, explaining whether legal abortion was good for women and the communities in which they lived. Although some resisted a focus on the costs and benefits of abortion, this shift in the terms of the debated sparked discussions about poverty and abortion, the role of government, the changing American family, the influence of abortion on women’s health, and the nature of scientific uncertainty. And surprisingly, as discussion turned to policy costs and benefits, polarization deepened. Both sides disagreed not only about foundational rights but also about the basic facts.