Encouraged by glowing reviews at numerous websites, I wangled the sainted Library staff of University Near Here to borrow me a copy of The Devil's Pleasure Palace by Michael Walsh, through the magic of the Boston Library Consortium.
Walsh's thesis (to the extent that I can understand it) is that the Left is not just full of bad ideas. It's fully of unholy ideas, their goal being to further the work of the Serpent in the Garden of Eden. Walsh doesn't (quite) mean this in the sense that Bernie Sanders literally shuffles off to a top-secret Black Mass every so often. (That would be neat, though, kind of the flip-side of the Republican gatherings portrayed on The Simpsons.)
Instead, the Left has (mostly semi-consciously) bought into Satan's side in his argument with God, succumbing to his false promises and temptations. Walsh frames this mostly as a takedown of the so-called "Frankfurt School" of criticism and philosophy, which sought refuge in America after fleeing Nazi Germany in the 1930's. Their baneful influence goes from strongholds in Academia into various niches of pop culture, politics, music, and art, whence they wage war on tradition, morality, family, and freedom.
Walsh writes from the standpoint of a devout Catholic, and he doesn't make a lot of effort to phrase his arguments to appeal to those of us less-than-devout folk. Still, if you buy that Christian theology is speaking (at least) a metaphorically true story about good/evil human nature, and its relationship to the real world, you can find quite a bit of insight in the work.
On the other hand, as Walsh points out, one of the Left's heroes, Saul Alinsky, really did write about "the first radical known to man who rebelled against the establishment and did it so effectively that he at least won his own kingdom -- Lucifer." Your enemies can sometimes make your case for you.
It's also kind of a fun read. Walsh bases his argument not just on the Good Book, but also the epic works spun out thereof: Marlowe, Goethe, Milton, et. al.. If those are a little heavy for your tastes, don't worry: Walsh also throws in references to Chinatown, Rosemary's Baby, and High Noon.
It's short, just slightly over 200 pages. If I had to quibble, it seems like a stitched-together book of independent essays rather than a coherent work with a sustained argument. People with a deeper grounding in classical literature and music than I will probably get more out of it than I did.