In The Gulag Archipelago, Solzhenitsyn noted that Shakespeare’s evildoers were content to commit only a handful of murders. They stop killing, Solzhenitsyn explained, because “they have no ideology.”

This pithy observation succinctly distinguishes Macbeth from mass executioners Stalin, Mao, Che and Saddam. But what explains the curious fact that intellectuals can apply critical thinking to the study of Shakespeare’s murderers, while ideological massacrists inspire—in leftists—the very opposite: a lapse in critical thinking so egregious that it amounts to a pathology?

You’ll find persuasive answers in the just-published United in Hate: The Left’s Romance with Tyranny and Terror, by historian Jamie Glazov. Glazov is the managing editor of FrontPage-Magazine, a popular online conservative Web site with 500,000 regular readers, published by former leftist turned conservative David Horowitz.

United in Hate chronicles a century of the left’s serial romances with totalitarian utopias—Russia, China, Vietnam, Nicaragua, Cuba and, today, “Palestine”—on which it has staked its hopes for a world cleansed of iniquity.

Historical circumstances may differ, but Glazov asserts that wherever “believers” in a salvational ideology congregate, you will find a keen appetite for revolutionary bloodletting:

“The less brutal an ideology is, the less interest the average believer has in it … [T]he fellow travellers always flocked to communist regimes in largest numbers when the mass murder had reached a peak—Stalin’s terror, Mao’s Cultural Revolution, Pol Pot’s killing fields.”

The left’s love affair with Communism up to the fall of the Berlin Wall in 1989 had logic to explain, if not excuse, it. Although Marx didn’t disguise his real goal—“everything that exists deserves to perish”—superficially, Marxism imagines a utopia that seems consistent with enlightened ideals.

But leftists’ replacement of communism as their ideological icon with the strange bedfellow of Islamism is more puzzling. True, both hate the West and promote wholesale violence in their triumphalist crusades. But the left is atheistic, sexually egalitarian and obsessed with “social justice.” Islamists are theistic, patriarchal and shariah-bound.

Glazov takes us on “the believer’s totalitarian journey” to explain the paradox. The believer, Glazov says, begins with an acute sense of alienation from his own society. A secularist, he nevertheless yearns for redemption, so finds a “secular shariah” in any totalist world, even Islamism, “where no individuality exists, and where human estrangement is thus impossible.”

The believer does not seek truth, he seeks submission to a movement. The price for this cultural orphan’s acceptance in his adoptive “vast community” is the amputation of residual emotional ties to his own. Henceforth, the believer must see the flaws of his own society as the keys to all the world’s evils. Once inducted, losing membership in the community becomes unthinkable.

And so he stops thinking. Logical and moral contradictions disappear. For now he needn’t “know” what is plain to see about the ever more oppressive real-world effects—the suffocation of free speech, the arbitrary imprisonment, gulags, terror bombings and stonings—of the utopian system he commits to.

The disciplined ferocity of Glazov’s indictment of leftist ideologues has its roots in personal experience. Glazov’s family arrived in America when he was five (his father, Yuri Glazov, was one of the dissidents who signed the “Letter of Twelve” in 1968). He was shocked that “while we were cherishing our newfound freedom, we encountered … intellectuals in the universities who hated my parents for the story they had to tell … Back in Russia, dissident intellectuals risked their lives when they pronounced one word of truth … In America, most of the intellectuals who surrounded us scoffed at the importance of real intellectual freedom … they demonized their own society.”

United in Hate is diabolically entertaining in its attack on the intellectual corruption that ensues when celebrity leftists’ high moral self-regard collides with their comically low self-awareness. The poster girl for such “useful idiots” was American writer Mary McCarthy. In Vietnam, apprised of the communists’ Hue massacre of about 3,000 South Vietnamese civilians, she commented: “There is no way of knowing what really happened … I should prefer to think it was the Americans.”

Glazov serves up a long list of other terminally naive political and cultural pilgrims who left their critical faculties at the border of the totalitarian societies they visited. They perceive ruthless dictators as wise, godly father figures (Steven Spielberg said that meeting Castro was “the most important eight hours of my life.”) They marvel uncritically at Potemkin villages, mistake the order of police states for social contentment and assume that the generous and kindly treatment they receive is the norm.

In chapter-long critiques, special contempt is reserved for Islamismsupporting feminists, homosexuals and Israel-hating Jews—useful jihidiots, so to speak—all of whom are treated by the very Islamists they support with special contempt. (At a May, 2004, rally for Palestinian rights in London, Islamists forced gays to stand at the back and shouted them down when they tried to speak.) Glazov’s withering scorn for Western feminists who ignore gender apartheid and female suffering in Islamist regimes applies equally well to all: “Better to let women [gays and Jews] suffer under a vicious regime than to admit that there are cultures to which the West is superior.”

United in Hate is a compelling, fast-reading polemic, offering original insights on a riven Western culture whose ability to acknowledge and defeat the enemy within will decide our historical fate. Read it and then, since it won’t be on curricula or available in campus bookstores for the foreseeable future, pass it along to a university student. Inside the very crucible of cultural self-loathing, their need is greater than yours.