Very briefly, this book answers the instapundit's favorite question: "why are leftists such cesspits of hypocrisy?" in one sentence: reality supports conservative belief, but forces leftists to choose between recognizing the emptiness and historical absurdity of their core beliefs or holding themselves hostage to those beliefs by escalating their commitment through everything from littering and lying, to murder and the deliberate undermining of economic, educational, and social opportunities for everyone.
Put differently: socialist values are basically Christian values, but socialist action normally supports and expresses the opposite values. Just recently, for example, some conservative commentators have been horrified to discover that democrats typically prove to have been doing whatever the latest horrible thing is that they accuse republicans of, but this form of projection has been standard procedure for the left since the French Revolution with those most personally involved screaming "that's bad, evil, immoral, illegal" with genuine sincerity while doing whatever it is. This is definitional insanity: a consistent set of behaviors in which people truly believe themselves to hold and represent one clear set of moral values, but cannot stop themselves from acting in direct opposition to those values at every opportunity.
The ultimate explanation for this behavior is that socialism is a cult whose prophet and prophecies -misinterpretations of the work of Thomas Malthus - have failed. That mistake, really the belief that human economic interaction is about resources and access to resources, is what drives socialist thought while the consequence that every socialist government, and every faux malthusian prediction ever tested against reality, has failed drives the frustration, insanity, and violence.
We can observe the left's behavior without understanding or judging it. In general the behavior we see can be summarized as a collective commitment to shouting their allegiance to basic Christian (and thus American) values while acting in opposition to those values. That's definitionally insane, but it is happening all around us, every day - ask any of the screaming harridans who protested the Kavanaugh confirmation and they'll tell you they're committed to the ideals of freedom, human rights, truth, and the rule of law - and yet their actions showed them spitting in the face of all they believe in, all that's good about the American judicial and political system.
Their behavior has to change, but we can't help them make that happen without first understanding it, and understanding starts with honest description. Although many highly visible leftists are so politically focused they're intolerable, most ordinary democrats seem like sane, sensible, superficially educated (i.e.they present as literate, but have little or no factual knowledge of science, history, or western culture), and reasonably intelligent people you'd be glad to have as friends or neighbors - until the conversation touches on politics and you realize they've placed themselves beyond the reach of reason in this one area of their lives. You get together for a nice dinner: their oldest is in university but won't study, yours drives too fast, their dog isn't quite as gassy as yours, and everyone agrees the Twins will make it to the playoffs this year - but then someone brings up politics and it turns out they voted for Clintons every time; think Kavanaugh a rapist, see Trump as a Hitler wannabe, adore John Kerry and Jane Fonda, and think Cuba a successful social democracy with great medical care for everyone.
That behavioral dichotomy demonstrates a limited, but very real, form of insanity in which the person's actions in the political context absolutely contradict their own values and most deeply held beliefs. Thus they really do believe in civilized values and human rights, but instantly sever relationships with old friends who admit to thinking that the words "Peace and Love" don't belong on posters of Mao Tse Dung and Che Guevara; abhor political violence and think the NAZIs epitomize Evil but excuse and even support Antifa; hate racism but insist that racial quotas be applied everywhere; value American rights and American freedoms but see nothing wrong with jailing Nakoula Basseley Nakoula on a pretext; demand rational analysis and reasoned argument from everyone on everything, but respond to almost any factual political statement you make with a vituperative ad hominem attack either on you or on some other conservative somewhere or somewhen.
The behavior is utterly irrational but typical for cultists in the later stages of delusion - exactly that chronicled by Leon Festinger and his colleagues in their study of believers who seem perfectly normal in their everyday lives, but repeatedly double down to the point of violence and suicide on loyalty to a prophet whose prophecies have publicly and undeniably failed.
So, for the progressive left, which prophet and what prophecy? Not Thomas Malthus as he actually was, but Malthus as misread, misinterpreted, and misused by nineteenth century European cafe intellectuals like Hegel, Schopenhauer, Nietzsche, Marx, Frege, and Heidegger.
Scratch any leftist and you'll find the foundational belief: there are too many people, the world has limited resources, and we're all going to die. It's nonsense, it's the lifeboat earth fallacy, and it's not what Malthus actually thought, but the belief identifies the prophet and the source of the prophecy that failed, that continues to fail: the future the progressive left both most fears and most assiduously strives to create.
At base the prophecies driving today's progressive movement grew from the social needs and limitations of 19th century, mainly German, cafe intellectuals using unintelligibility as a kind of emperor's clothes to claim and maintain a symbiotic relationship with those whose goodwill and credulity they depended on for their livelihoods. In reality Malthus was a hard working English vicar fascinated by human behavior under stress who ultimately understood the role of markets in individual behavior well enough to come away fairly optimistic about humanity's future, but that isn't how he was understood by the self proclaiming elites of the day. Those people generally struggled through some early translations of his writings, stroked their collective beard, and announced to the gathered pretenders that everything Malthus ever said or thought was about the allocation of, and thus the struggle for, limited resources - and then, after several decades of profound thought and good living, added a little over-simplified Darwin to derive their survivalist programs for the most brutal forms of eugenics and "scientific" national socialism in which the concept of ownership is done away with and the leadership, which owns nothing, controls everything and everyone.
Thus the prophecy that fails is in part that the socialist ideas developed on the assumption that everything is ultimately about access to resources should provide a better life for those who attempt to implement them - a consequence reality consistently denies. Think of the history of modern progressives from Marx to Soros as Jim Jones and apostolic socialism writ large: not just 900 dead in Guyana after thirty years of disappointment and re-entrenchment, but as over 200 million dead and ten times that many lives destroyed in a century of world wide disappointments and retrenchments ranging from the Bolsheviks in Russia to Antifa in Berkeley.
Normally, of course, cults die out as their prophecies fail, the less committed fade from sight, and the more committed eventually take what's left of the movement with them when they die. In this case, however, colleges and universities reverently teaching ideas derived from poseurs like Hegel, Nietzsche, and Marx continually churn out new Bernie Bros - and the obvious failure of any form of socialism to ever produce the promised result merely separates the true devotees, who double down on their earnestness each time there's a new Pol Pot or Venezuela, from those able to face reality.
To put all this in a more current, mid October 2020, context, there may be as many as sixty million people who routinely vote democrat in the United States, but only a small proportion of them actually invest significant physical and emotional resources in working for the party and an even smaller group, possibly numbering no more than a few thousand, truly understand and support the progressive left's use of the party in its attempt to remake the American political and economic system in its own totalitarian image. Thus there may only be a million or two of the true useful idiots - committed believers who have no idea that the leadership is wearing the democratic party like an Edgar suit but teeter on the edge of violence as an ever increasing proportion of their refusal to face reality expresses in hatred for conservatives and conservative causes.
Thus the bottom line offered in this book is both appallingly simple and hard to accept: all of the left's thinking, the entire progressive world view, is based on the assumption that human economic competition and co-operation are based on physical resources and because that's wrong, everything they do, every policy they develop, crashes into reality and fails - and that failure then sets up the internal conflicts leading to the behaviors we see.