To push a metaphor for a moment — if the Constitution and the Bill of Rights were the bones of the house that all Americans inhabited, then the Protestant Mainline was a combination interior decorator, building inspector, homeowners’ association and zoning committee. Any question that the liberal order didn’t answer, across most of our history, was answered by Protestant consensus or litigated by intra-Protestant debate. (What were the limits of religious liberty? Should society regulate sex, and how? Should society regulate alcohol consumption, and how? What values should be taught in schools and universities?) And when the Mainline couldn’t come to an agreement, as in the long theological dispute over slavery and racial equality — well, then part of the house burned down and had to be repeatedly reconstructed.
But all that belongs to the past, because in the decades after Eisenhower, the Mainline suddenly collapsed — declining numerically and losing overt influence in all the institutions, elite and local alike, that it once animated and defined. What took its place, in the upper echelons on the meritocracy, was an assumption that liberalism didn’t need a religious ghost in its machine, that you could just have a liberal culture instead of a Protestant culture, and all the important questions could be worked out through reasoned arguments that required no theological priors, no Bible-bothering, no authority higher than the Supreme Court or capital-S Science.