The loss of religious moderates

"While one group of Americans has tended to withdraw from active involvement in faith-based communities, another group is as fully involved as ever. While the fraction of the population that is entirely disconnected from organized religion has increased, the fraction that is intensely involved has been relatively stable. In other words, religious dropouts have come at the expense of those whose religious involvement was modest but conventional. The result is that the country is becoming ever more clearly divided into two groups--the devoutly observant and the entirely unchurched. (Some might see here a certain parallel to trends in politics--more true believers, more dropouts, and fewer moderates.) This is the sociological substratum that underlies the much discussed "culture wars" of recent years."

(p. 75)

from Robert Putnam's "Bowling Alone"