Previously posted on SSRN.


At the heart of American constitutionalism is an irony. The United States is constitutionally committed to religious neutrality; the government may not take sides in religious disputes. Yet many features of constitutional law are inexplicable without their intellectual and cultural origins in religious beliefs, practices, and movements. The process of constitutionalization has been one of secularization. The most obvious example is perhaps also the most ideal of liberty of conscience that fueled religious disestablishment, free exercise, and equality was born of a Protestant view of the individual’s responsibility before God.

This Essay explores another overlooked instance of constitutional secularization. Many jurists and scholars count the modern Supreme Court’s progressive interpretations of constitutional rights and equality provisions among the nation’s greatest achievements. Scholars have given little attention, however, to the religious origins of those decisions. This Essay suggests that they were heavily influenced by Christian ideas of moral and social progress.

Nineteenth- and twentieth-century Christian intellectual and political movements grounded in post-Enlightenment views of eschatology—or “the last things”—contributed to a doctrine of American civil religion that in turn contributed to the Supreme Court’s reasoning. That doctrine of American civil religion holds that America has a special moral destiny. From at least the early nineteenth century, many Americans have believed their nation to be a “city on a hill,”2 built and directed by Providence to lead the world in moral reform. The doctrine is well captured by a phrase first written by a nineteenth-century Unitarian minister but popularized by Martin Luther King Jr. and Pres- ident Barack Obama: “The arc of the moral universe is long, but it bends towards justice.”3 Numerous Presidents, of both political parties, have further distilled the concept by emphasizing the importance of being on the “right side of history.”4

Beginning in the mid-twentieth century, the Supreme Court deployed a secularized version of this doctrine in constitutional decisions about rights and equality. The incorporation of the Bill of Rights, the “evolving standards of decency” doctrine under the Eighth Amendment, and the “new insights” into liberty and dignity that inspired the landmark decision to extend the marriage rights to same-sex couples all implemented the beliefs that morality is progressive and the U.S. Constitution incorporates that progress.5 Though many current members of the Court reject this view of constitutional interpretation, most scholars still hold it.6 They do not appreciate, however, that the intellectual origin of this view is a theologically controversial position on an esoteric question of Christian theology, strained through the generalizing dynamics of American civil religion.