Confession: I stopped writing this essay on “O Holy Night,” soured by something I couldn’t name, bogged down by the online research. I set it aside, but the urge returned and I started it up again several days later. Then it happened again, an edgy, almost negative feeling as I read article after article to research its story, so I stopped a second time. And now, here I am again, picking it up again, irresistibly drawn to its theme, even as something’s still bugging me.I think I’ve figured it out: what I’ve always thought of as a humble yet glorious, affecting Christmas carol, turns out to have a vaguely spicy story (or three or four – depends on the writer’s angle) behind it. Better put, a story of what happened after its premiere at midnight Mass in 1847 in Roquemaure, France. There’s political intrigue. Atheists and socialists versus the French Catholic Church, a ban, with a Jew—or maybe not—involved, and later, an abolitionist, a whole movement, and, yeah, I’ll stop right there. It...