Samuel Moyn, a professor of law and history at Yale, maintains that today’s liberals are feeble even when they manage to take their own side. The central thesis of his daring new book, “Liberalism Against Itself: Cold War Intellectuals and the Making of Our Times,” is that Cold War liberals and their contemporary heirs do not champion a stirring vision so much as they adopt a self-protective crouch. Recent examples abound. In an excellent essay about misogyny on the alt-right published last week, Atlantic staff writer Graeme Wood ends by thanking reactionaries for providing liberals with a renewed sense of purpose. “Unchallenged, liberalism’s defenses waned,” he concedes, “and liberals forgot, temporarily, why their cause was worth defending.” They also forgot — and more than temporarily — to not just defend but actively promote their ideals. Meanwhile, New York Times stalwart Ross Douthat recently noted that the Democrats’ presidential campaign is less about touting their own policies than about “abnormalizing” the abuses of their opponents.

The ignominies of Jan. 6 were indeed abnormal, but criticism of the enemy, Moyn argues, must be supplemented with something more substantive and sustaining. If liberalism’s appeal is increasingly tenuous, it is at least in part because it advertises itself in such singularly uninspiring terms. As Moyn, a reluctant liberal, so pithily puts it, “Cold War liberalism was a catastrophe — for liberalism.” But perhaps it is not too late to save the outlook from its own pathologies.

Detractors on both the left and the right tend to sketch the same caricature of the prototypical liberal: a chipper rationalist who is scornfully secular, naively sanguine about humanity’s prospects for self-improvement and devoted to the philosophy of the Enlightenment. “Liberalism Against Itself” takes evident relish in turning these historically dubious dogmas on their heads.

The Cold War liberalism that emerged in the 1940s and ’50s, Moyn claims, was a paranoid and profoundly pessimistic posture, defined almost entirely in opposition to Soviet communism and German and Italian fascism. American historian Arthur Schlesinger Jr. and French philosopher Raymond Aron are most frequently associated with this mid-century turn, but Moyn opts to focus on thinkers he regards as comparatively underappreciated, including the Harvard political theorist Judith Shklar, the Oxford philosopher Isaiah Berlin, the roaming philosopher of science Karl Popper, the liberal-turned-neoconservative Gertrude Himmelfarb, the all-around intellectual celebrity Hannah Arendt and the literary critic Lionel Trilling.

For the most part, “Liberalism Against Itself” is ambivalent about its cast of characters. Moyn musters grudging respect for everyone except Popper, whose abrupt shift from thoughtful philosopher of science to vulgar political bloviator he disdains. By far his favorite of the assembled personae is Shklar, the first woman to receive tenure in the Harvard government department and the only figure in the book to at least struggle against the tides of Cold War liberalism before succumbing to them. The diagnosis she provided in her debut monograph — that the lukewarm liberalism of her contemporaries was, as she writes, “another expression of social fatalism, not an answer to it” — underlies much of Moyn’s analysis. Still, even a thinker as canny as Shklar capitulated to the defeatism of the era eventually. By 1989, she was defending what she famously termed “the liberalism of fear.”

The misanthropic bunch profiled in Moyn’s book is as radically unlike the upbeat liberals of the familiar stereotype as possible. Moyn shows that they rejected both the rationalist’s trademark faith in reason and the doctrine of perfectionism, according to which the state is in the business of drawing up comprehensive blueprints for how we ought to live. Instead, they gravitated toward a dire picture of people as “dark and aggressive, requiring self-management.”

The sulky postwar formation that Moyn depicts owes a great deal to Christian brooding on original sin, as well as to Sigmund Freud’s then increasingly popular conception of the self as impulsive and destructive. Predictably enough, given their low opinion of their fellow creatures, Cold War liberals also eschewed the notion that humankind is ascending in a broadly linear fashion toward the sunny heights of moral elevation. “No longer the agent of an unfolding plan to produce a better and more fulfilled humanity,” Moyn writes, “liberalism had to be defended as an elemental and eternal set of principles that required the renunciation of ‘progress.’”

The advent of this mistrustful ethos was not organic: The Cold War coterie rewrote their tradition in the shadow of the Soviet threat by laboriously constructing both a new canon and an accompanying “anti-canon.” Allies, such as Freud and the 19th-century British politician Lord Acton, were ushered into fashion; antagonists, such as Jean-Jacques Rousseau and G.W.F. Hegel, were escorted out.

The Cold War liberals might have been misguided in banishing their predecessors — but their desire to revise their history demonstrates that their movement once took a different form. The liberal tradition, Moyn assures us, contains the seeds of its own salvation. His ultimate contention is not that we should abandon liberalism but that we should resuscitate an earlier and more rousing wave of thinkers. Examples include John Stuart Mill, who called for inventive “experiments in living,” and the 19th-century philosopher T.H. Green, who wrote that the role of the state was to “maintain the conditions without which a free exercise of the human faculties is impossible.”

Though “Liberalism Against Itself” is skewed more toward critique than reform, it stresses that there are ample “liberal resources for surpassing the limits of Cold War liberalism,” the logic of which continues to permeate political discussion. These resources include a “commitment to the emancipation of our powers, the creation of the new as the highest life, and the acquisition of both in a story that connects our past and our future.” The refurbished liberalism that Moyn implicitly recommends would not fashion itself primarily as a bulwark against Donald Trump and his populist cronies. Instead, it would relinquish its embarrassment about its debts to the Enlightenment and extol progress without apology. Above all, it would actively celebrate and support the human capacity for creative self-expression.

The general point that Cold War liberalism is deflatingly unambitious is both refreshing and convincing, but I have respectful quibbles with some of the details in “Liberalism Against Itself.” Moyn’s interpretations can be idiosyncratic, and as his title suggests, he often reads thinkers against their own explicit avowals. Berlin protested that he had “never dreamt of implying that [the Enlightenment] was all that bad,” but Moyn alleges that “he had in fact implied that very thing.” Arendt “repeatedly declared she wasn’t a liberal,” but “her very attempt to strike out on her own in developing a new vision of freedom proved hostage to many Cold War liberal premises.”

Still, Moyn makes a compelling case for his unconventional readings, and the qualities that make them contentious also make them exhilarating. Provocations are not flaws in a book designed to deliver a shock to the system, and if I find much to question in “Liberalism Against Itself,” it is only because I find much to ponder.

In particular, I wonder if Berlin has more to offer than Moyn grants. He characterizes the Oxford icon as colluding in “expurgating perfectionism from the version of the tradition he defended” — and while it is true that Berlin did not justify liberalism in terms of individual self-realization, it is also true that he did not regard it as a mere barricade against barbarism. Instead, he understood it as intent on nurturing a different value — diversity. Liberalism, by his lights, was a matter of acknowledging and respecting the “plurality of values, equally genuine, equally ultimate.”

Berlin worried that pluralism might not amount to an especially thrilling program. A liberal call for affording “each human group sufficient room to realise its own idiosyncratic, unique, particular ends without too much interference with the ends of others, is not a passionate battle-cry to inspire men to sacrifice and martyrdom and heroic feats,” he regretfully confessed. But I think he may have underestimated the power and dignity of difference. What could be more touching than his insistence that each culture is “of infinite value, as souls are in the eyes of God”? Why should liberals limit themselves to fostering a single sort of perfection when we could enjoy “as many types of perfection as there are types of culture”?

These are the kinds of questions prompted by books that begin indispensable conversations. “Liberalism Against Itself” pokes helpful holes in the unfortunately ubiquitous attempts to reduce liberalism to rationalism — and thereby to paper over the potent frictions that have always riven the tradition. It also issues a welcome invitation to liberals to make better sense of their own inheritance, and to take their own side for once.

Becca Rothfeld is the nonfiction book critic for The Washington Post.

Liberalism Against Itself

Cold War Intellectuals and the Making of Our Times