“Meanwhile, a widespread decline in churchgoing and religious affiliation had contributed to a growing anxiety among conservative believers.” Statements like this are uttered with such confidence and frequency that most Americans accept them as uncontested truisms. This one emerged just this month in an exceedingly silly article in The Atlantic on Vice President Mike Pence.Religious faith in America is going the way of the Yellow Pages and travel maps, we keep hearing. It’s just a matter of time until Christianity’s total and happy extinction, chortle our cultural elites. Is this true? Is churchgoing and religious adherence really in “widespread...