Relations between American democracy and religion have always been somewhat equivocal.

On the one hand, moral and ethical principles derived from the Judeo-Christian tradition have been a major source of democratic values. Religion was an important motivating factor in both the colonization of North America and the American Revolution. The Founding Fathers set such high store by religion that they included its free exercise along with free speech and a free press among the liberties specifically protected by the First Amendment to the Constitution. Organized religion played a key role in such drives to perfect democracy as the abolition of slavery, the enactment of woman's suffrage, and the civil rights struggle of the 1960s. Perhaps most important, the so-called Protestant ethic provided the moral bedrock on which republican institutions were built.

On the other hand, democratic theorists and much of the general public have been wary of the absolutist social outlook often associated with religion. Practically all religions claim to embody ultimate truths about the nature of the universe and the human condition. At some level, therefore, they can hardly be tolerant of rival beliefs. Religious bodies can avoid social intolerance by acknowledging that human imperfection clouds and corrupts the judgments of all institutions, including the churches, or by limiting their social pronouncement to broad moral directives. In practice, however, individuals or institutions claiming to represent transcendent moral authority are often tempted to attach certainty to their opinions on complex issues in secular politics.