The American church historian Sidney Ahlstrom once described J. Gresham Machen’s Christianity and Liberalism as “the chief theological ornament of American Fundamentalism.” While fittingly complimentary, this assessment is unfairly restrictive. Machen never cared for the term “fundamentalism.” He thought of himself as no more or no less than an orthodox Christian, confessional Presbyterian, and professor of New Testament, serving at Princeton Seminary until he resigned in 1929.

To be sure, Machen affirmed the doctrine of the plenary inspiration of Scripture. The Bible, he says, is a “true account” of divine revelation whose entire text is insured by the Holy Spirit. But this claim did not make Machen’s theology different from the historic teaching of his church or the heritage of Princeton Seminary. Inerrancy is not the teaching upon which the Church stands or falls. “There are many,” he wrote, “who believe that the Bible is right at the central point, in its account of the redeeming work of Christ, and yet believe that it contains many errors.” While insisting on a biblical basis for Christianity, Machen did not believe, like the stereotypical fundamentalist, that all points of the Bible are of equal importance. How Machen makes his argument concerning what is and what is not of central importance is especially relevant, I think, to the readers of First Things because it speaks to the essence of theological reflection apart from the particulars of religious loyalty.

In Christianity and Liberalism , Machen separates himself doctrinally from a number of Christian groups. He says that premillenialists are wrong to try to map out the specifics of Christ’s return. He rejects the Catholic allegiance to the Pope as the Vicar of Christ as well as the more general Anglican teaching that the office of bishop is a necessary mark of the Church. Against Wesley and Arminianism generally, Machen asserts that the human will is not free to choose salvation. Luther, he declares, was mistaken concerning the Real Presence of Christ in the Lord’s Supper. Despite these serious doctrinal disagreements, Machen affirms that those with whom he disagrees are part of the Christian family. While separated over doctrine, they are one in affirming the central object of faith: the exclusive lordship of Jesus Christ.

The denial of the object of faith is, according to Machen, the chief peril of theological liberalism. Liberalism treats historic doctrines, as well as confessional conflict, as the leftovers of a superseded supernaturalism. To be modern, says the liberal, is to interpret the world as a self“enclosed process in which there is no place for divine intervention. It is to understand the phenomenon of religion not as the encounter with an Other, but as the projection of human thought and desire. According to liberalism, the divine means nothing more than a vague feeling of an affirming “presence.” This “presence” symbolizes, like some ancient demiurge, “the mighty world process itself” or “the highest thing that men know.” The content of Scripture is reconceived as the symbolic quest for personhood that is to be judged according to how it advances “the healthy, harmonious, and joyous development of existing human faculties.”

Against such a teaching, all Christians”indeed anyone who respects the fundamental nature of religion”must object. To transform religion into a form of human subjectivity is a deeply hostile act of intellectual hubris that seeks to destroy the authority of religion in public life. This is why Machen declares that “despite the . . . use of traditional phraseology, modern liberalism not only is a different religion from Christianity but belongs in a totally different class.”

One contemporary observer who agreed with this assessment was, of all people, Walter Lippmann. In A Preface to Morals (1929), one of the most highly regarded books of its day and still considered a classic interpretation of American culture, Lippmann, a secular critic and nonbeliever, took the side of Machen in the debate against theological liberalism. To separate the ideas and values of Christianity from external events goes against the fundamental nature of religious belief, Lippmann argued. “There is gone that deep, compulsive, organic faith in an external fact which is the essence of religion for all but that very small minority who can live with themselves in mystical communion or by the power of their understanding.” Because Machen understands the essential connection between religion and historical externality, he “goes to the heart of the matter.” Thus Lippmann judged Christianity and Liberalism one of the most important books of the decade following the Great War. Seventy years later, and for precisely the same reason, the book retains its importance.

Walter Sundberg is Professor of Church History at Luther Seminary in St. Paul, Minnesota.