Francis Schaeffer's 1982 message to the Presbyterians at Coral Ridge Presbyterian Church in Fort Lauderdale, Fla., was pretty simple: the philosophy of modern society is humanism, and humanism means death.

The speech was part of Schaeffer's book tour for A Christian Manifesto, which had been published the year before. That book and tour, along with 1976's book and film series How Shall We Then Live? and 1979's book and film Whatever Happened to the Human Race?, all made a sustained argument about the need for Christian activism. The pro-life movement, as such, can be traced to these arguments; the religious right as a "bloc" and a single, mobilized, political entity, was formed in part by these efforts. Schaeffer made the historical and ...