Opposition to legalized abortion is part of the bedrock of conservative politics today. Yet despite the almost seamless integration of the contemporary pro-life movement into the Republican Party, the relationship between the two is historically and ideologically peculiar. The pro-life movement was formed largely by Catholics, not conservative Protestants. Moreover, the background of the movement was to a large degree rooted in progressive Catholic ideas about social justice and the (progressive) experiences of many early activists in advocacy for peace and the poor. At the same time, Republicans did not initially embrace pro-life activists following the 1973 Roe v. Wade decision. Twenty years ago, then, there was nothing inevitable about opposition to legalized abortion becoming one of the central social issues around which conservative mobilization and electioneering revolves. This research looks at how the pro-life movement has moved from a progressive, Catholic orientation to a conservative, Protestant orientation, as part of a explicit social movement strategy by conservative leaders to coop the movement. I am also interested in what implications this historical process has for the current abortion debate. Data from this project draws on historical sources, General Social Survey data, and data I originally collected for by book on the pro-life movement.