The inhabitants of this penumbra still identify with Christianity, but they lack the communities, habits and support structures that make the religious path (somewhat) easier to walk. As a result, this Christian-ish landscape seems to produce more social dysfunction, more professional disappointment and more personal disarray than either a thoroughgoing secularism or a fully practiced faith — which makes it ripe territory for Trump’s populist appeal. And his occasional nods to religious faith — like, say, his promise to make store clerks say “Merry Christmas” instead of “Happy Holidays” — are well tailored for voters for whom Christian identity is still a talisman even when an active faith is all but gone.

Then among Americans who do still have an active faith, Trump has exploited the widening gap between what many conservative Christians assumed about the relationship between their country and their faith, and what the last 10 years or more of social and political change have revealed about the nation’s drift. Here’s how Ben Domenech recently described this psychology of disillusionment:

Evangelicals have for decades believed that the country was more conservative than not, more Christian than not. The bipartisanship on religious liberty and the civic faith of the country was conducive to that. Now they’ve woken up to a reality in the Obama years that this was a polite fiction. They worry that coaches getting fired over praying at schools, fire chiefs getting fired for citing Scripture, bakers getting bankrupted over their refusal to bake a cake — their entire perspective on Christian faith as a key element of what made America great has been swept away.

Faced with these shifts, many religious conservatives have contemplated a partial retreat from political activism, a quest for internal cohesion and cultural resilience that Rod Dreher of The American Conservative has called “the Benedict Option,” after the founder of Western monasticism.

But others clearly look at things a little differently. If this is really a post-Christian society, they seem to be thinking, then Christians need to make sure the meanest, toughest heathen on the block is on their side. So it makes sense to join an alliance of convenience with a strongman, placing themselves under his benevolent protection, because their own leaders have delivered them only to defeat.

And the lure of the strongman is particularly powerful for those believers whose theology was somewhat Trumpian already — nationalistic, prosperity-worshiping, by turns apocalyptic and success-obsessed.

With the steady post-1960s weakening of traditional Christian confessions, the preachers of this kind of gospel — this distinctively American heresy, really — have assumed a new prominence in the religious landscape. Trump, with his canny instinct for where to drive the wedge, has courted exactly these figures. While more orthodox Christians have kept him at arm’s length or condemned him, he’s wooed televangelists and prosperity preachers, and pitched himself to believers already primed to believe that a meretricious huckster with unusual hair might be a vessel of the divine will.

Which he is not, save perhaps in this sense: In the light of Trumpism, many hard truths about American Christianity — its divisions, its failures, its follies, its heresies — stand ruthlessly exposed.

And the truth, we’re told, will set you free.