Diversity is the hallmark of religion in America. Indeed, America's was the first society not merely to tolerate some diversity in religious behavior, but to make voluntary church affiliation–and hence the maintenance of a pluralistic religious environment–the very basis of its church-state system (Hudson, 1953; Latourette, 1941: 425–426; Lipset, 1967: 182). Unlike their European ancestors, the new Americans steadfastly refused the establishment of a national church, both because the rationalists among them feared the imposition by government of any religious orthodoxy, and because the radically orthodox feared any authority not wholly and reliably scriptural (Mead, 1954a, 1954c, 1956: 333–334; Miller, 1935; Sperry, 1946: 44–58).

The result has been a proliferation of religious organizations through American history. Although the rate of innovation has not been constant, its accumulated products are everywhere evident along the American cultural landscape. This variety is duly represented in the Census's data on church membership. As Henry K. Carroll (1912: xiii-xiv) wrote in summarizing the returns from the Census of 1890: