In an irony appreciated by anyone who remembers the original anti-consumption, anti-Santa meaning of the “Reason for the Season” slogan, Fox and allies like the American Family Association focused on getting more Christmas into stores and shopping malls. For more than a decade, Fox News hosts have kept viewers updated on which stores were “in the Christmas spirit,” and the American Family Association, which operates nearly 200 radio stations in the United States, maintains its very own “naughty and nice” list for retailers.

As a result, the War on Christmas has moved one of the holiest Christian days out of the church and into the secular realm. That may suit conservative activists who promote Christian nationalism and want to see Christianity officially dominate the public sphere. But at a time when a new Pew Research Center study shows that only about half of those Americans who celebrate Christmas plan to do so as a religious holiday, the War on Christmas may be damaging Christian witness by elevating performative secular practices.

These days, even though Mr. O’Reilly declared “victory” last year in the War on Christmas, Fox News still gives the supposed controversy wall-to-wall coverage and has folded it into the network’s us-versus-them, nationalist programming. The regular Fox News viewer, whether or not he is a churchgoer, takes in a steady stream of messages that conflate being white and conservative and evangelical with being American.

The power of that message may explain the astonishing findings of a survey released this month by LifeWay Research, a Christian organization based in Nashville. LifeWay’s researchers developed questions meant to get at both the way Americans self-identify religiously and their theological beliefs. What they discovered was that while one-quarter of Americans consider themselves to be “evangelical,” less than half of that group actually holds traditional evangelical beliefs. For others, “evangelical” effectively functions as a cultural label, unmoored from theological meaning.

But if the conservative media has created a category of Fox evangelical converts, it has also influenced the way a whole generation of churchgoing evangelicals thinks about God and faith. On no issue is this clearer than guns.

In fall 2015, I visited Trinity Bible College, an Assemblies of God-affiliated school in North Dakota, to join the conservative evangelical students there for a screening of “The Armor of Light,” a documentary by the filmmaker Abigail Disney. The film followed the pastor and abortion opponent Rob Schenck on his quest to convince fellow evangelicals — the religious demographic most opposed to gun restrictions — that pro-life values are incompatible with an embrace of unrestricted gun access. I found Mr. Schenck compelling, and my editor had sent me to see if his target audience bought the arguments.

It did not.

As two dozen of us gathered for a post-screening discussion, I was both astonished and troubled, as a fellow evangelical, by the visceral sense of fear that gripped these young adults. As a child in the Baptist church, I had been taught to be vigilant about existential threats to my faith. But these students in a town with a population of some 1,200 saw the idea of a home invasion or an Islamic State attack that would require them to take a human life in order to save others as a certainty they would face, not a hypothetical.