There are many ways to approach the question of how far the United States is a standing reproach to the ‘secularisation thesis’, not least because there are many versions of that thesis. The strongest version, whose intellectual genealogy runs from Condorcet via Auguste Comte to Max Weber, suggests that religion is irrational and childlike, that modernity promotes rationality and maturity, and that in time religion will be extinguished because redundant. The weaker version argues that religion may be a continuing human need but is a private matter, confined to voluntary associations, but that public institutions (especially the state and education) are obliged to be secular. Within this latter version, one can discern two varieties, rooted in differing estimates of religion: the first mistrusts religion's moral influence as narrow, sectarian and intolerant, and hence incapable of furnishing a shared social morality for the public realm; the second thinks better of religion and acknowledges that it might promote, say, charity or altruism, but is conscious that religions are too plural and particularist to be allowed free rein, because their actions often generate social conflict and disharmony, and that, at best, religions can act in the public realm only when their idiosyncrasies are filtered out. Indispensable to these standpoints, with the exception of the last, is the presumption that, over time, there come to be a growing number of agnostics and atheists, who acquire cultural and social power, which is used either to extirpate or to quarantine the religious.