Liberalism is in crisis, we’re told, assailed on left and right by rising populists and authoritarians. The center cannot hold, they say. But if liberal democracy itself is under threat of collapse because of this weakened center, why are the great defenders of the “open society” such as Isaiah Berlin, Arthur Schlesinger Jr., Karl Popper, and Raymond Aron so little invoked? One would think that liberals today would be pressing back into service these robust thinkers of cold-war liberalism. But while not forgotten, their names are barely cited in contemporary political debates. One curious exception—that almost proves the rule, given its eccentric grounds—was when, last year, an Irish finance minister lauded Berlin for helping him deal with “the demands of corporation tax policy.” That is hardly using Berlin as a buttress against populism.

There remains much to be recovered from cold war liberalism for our historical moment. These thinkers had already learned the hard way that progress in the direction of a more liberal world is not inevitable. In a self-critical vein, they took seriously some of the charges that had been leveled against capitalist democracies in the 1920s and 1930s. But what Schlesinger outlined in an influential 1949 book called The Vital Center was not a matter of mere pragmatism, let alone triangulation between extreme left and right. These thinkers sought to craft a principled politics of freedom for the circumstances of the twentieth century. This was very different from the tendency of today’s disoriented centrists to pre-emptively enact the agenda of populists—for example, Hillary Clinton’s cynical call for Europe to stop aiding refugees, since, in her view, the migration issue just helps populists. Her underlying idea appears to be that one can defeat one’s political adversaries by imitating them. That is not what cold war liberals thought.

One obvious reason for cold war liberals’ relative exclusion from conversations today is that the cold war was to a great extent a struggle between grand narratives of warring political ideas (even if it was not just about political ideas). Berlin and Aron famously denounced the totalitarian utopias of the twentieth century as the “opium of the intellectuals.” Populists have no such utopian program, and they do not believe in historical determinism in the way many Communists did. Indeed, populism has no intrinsic ideology or doctrine of either left or right. Rather, populists claim that they, and only they, represent “the real people” or “the silent majority,” as they deny the legitimacy of their political competitors who are declared to be corrupt and “crooked.”

Berlin and Aron’s critique cannot apply here because populists have no use for appealing to intellectuals or the seduction of big ideas. Rather than looking forward to a perfected future, right-wing populists in particular conjure up a fantasized past of a homogeneous, pure volk. In fact, they tend to reduce all political questions to questions of belonging: they insinuate that those citizens who do not share their conception of the people do not properly belong to the people at all; if citizens criticize populists, they are quickly condemned as traitors. This explains why right-wing populists like Hungarian Prime Minister Viktor Orbán attack “liberal elites” and vulnerable minorities at the same time.

Trump, for his part, declares opponents “treasonous” and “un-American.” In a speech he gave in Warsaw, Trump’s rhetorical question—“Do we have the confidence in our values to defend them at any cost?”—could be mistaken for a soundbite from the height of the cold war, but tellingly, he followed it with another: “Do we have enough respect for our citizens to protect our borders?” With this, he conjured a world in which real Americans are constantly threatened by caravans of Middle Eastern terrorists and people from Latin America who can pass for citizens but might be enemies within.

Facing totalitarianism rather than populism, the cold war liberals always emphasized pluralism. By that they meant not just a pluralism of interests, which was at the basis of conventional mid-twentieth-century defenses of democracy as a system that lets interest groups compete peacefully, but also a pluralism of human values and what Schlesinger called “a genuine cultural pluralism” characteristic of a democratic society. Thinkers like Berlin and Popper stressed that the utopian state cannot realize a blueprint based on set values without riding roughshod over the rights of individuals—for values held by individuals were simply too varied and often incompatible. This principled pluralism, with its call to respect the diversity of individuals and groups, also helps to show why the populist notion of a unitary volk is so dangerous.

Cold war liberals like Arthur Schlesinger Jr. also sought to formulate a “fighting faith” to defend the vital center. They threw themselves into a battle of ideas, a side effect of which, they thought, was greater clarity about their own ideals. As Berlin once put it, “I have always said to myself that I preferred Jesuits to muddled men of good will. At least one knows what one is fighting for and against, and the weapons are kept sharp.” On other occasions, though, Berlin counseled moderation and warned that a political “faith” should not necessarily be answered with a “counter faith,” as though fanaticism required a fanatical response to be defeated.

Both liberal stances—longing for a “good fight” to affirm one’s identity, and a self-conscious espousal of moderation—are problematic today. Since populism offers no coherent creed, there is no Schlesinger-style “counter faith” to be crafted; in any case, liberals should be able to figure out what they stand for without needing enemies to help them define it. And being centrist or moderate is only an attractive position to hold if one can plausibly argue that two extremes are equally dangerous. There is no symmetry between right-wing populism and what is often labeled as left-wing populism in our time. One might not agree with their policy proposals, but neither America’s Bernie Sanders supporters and democratic socialists, nor Britain’s followers of Labour leader Jeremy Corbyn, are anti-pluralists. They may advocate “for the many, not the few,” but they are hardly operating with a notion of the pure people. (This is not to suggest that an inherently anti-liberal populism cannot be found anywhere on the left: Venezuela’s disastrous “socialism for the twenty-first century” is an obvious example.)

It is virtually forgotten that Schlesinger’s defense of the center also amounted to strengthening the non-Communist, non-Stalinist left (what Schlesinger called “the free left”), rather than a search for whatever might be the mid-position between left and right, or a studied bipartisanship. Berlin and Popper were effectively social-democrats who argued that a welfare state was indispensable for a decent society. Schlesinger railed against “the tyranny of the irresponsible plutocracy” and called for democratic control of the economy. This stance made cold war liberals very different from figures like Friedrich von Hayek, an avowed enemy of social-democracy and a major inspiration for the conservative movement in the US and Thatcherism in the UK.

Wanting to bolster a moderate center is no virtue when it is based not on principles but on an implausible equidistance. Populists rage against “globalism” and “open borders.” But who actually advocates completely open borders? Even in the academy today, proponents of truly global justice and the free flow of people are a distinct minority. When Popper defended the “open society,” he opposed both doctrinal intolerance and tribalism as a mind-set; the argument was epistemological, not one about immigration policy: open minds, not freely accessible territory. (Cold war liberals still generally favored the taking in of refugees; theirs was also a liberalism in the older sense of liberality, or generousness.)

Of all the cold war liberal intellectuals, Isaiah Berlin might seem the most in tune with populism’s culture war over national identity. Berlin, after all, was a life-long committed Zionist, with great sympathy for nationalism. He always emphasized humans’ fundamental need to belong and explained many of the ideological excesses since the eighteenth century with reference to a “state of wounded consciousness.” By this, he meant a sense of not being recognized, of having one’s way of life disrespected, of not being up to the supposed standards of a liberal cosmopolitan culture. In the age of Hillbilly Elegy, Berlin’s sensitive approach to the psychological sources of political discontent might seem especially useful.

Terms like “anger” and “resentment” are used routinely, reflexively, in contemporary commentary on populism, but these long-distance diagnoses can be patronizing. They also risk closing down serious debate by separating emotion from reason when, in fact, the two cannot be kept apart. After all, people are angry for a reason, and looking at their discontents primarily through a psychological lens makes it less likely that we ask them directly about those reasons and how they arrived at them. The other peril here is of excessive empathy, especially in the absence of any real encounters with “the people.” It is one thing to engage with people’s lived experience; it is another to take descriptions of that experience by demagogues, be they politicians or talk-radio figures, at face value. In an effort to understand—what Berlin referred to as Einfühlen, the process of identification with the thoughts and emotions of another—one becomes too understanding: the problem of tout comprendre, c’est tout pardonner. The pronouncements of those who claim to have fully understood the message that putative ordinary people themselves want to send—what Germans sometimes call Populismusversteher—can have pernicious long-term consequences. It is simply assumed that populists have revealed the truth of what is happening deep inside our societies, and sooner or later other parties will start to act on the basis of a seeming “truth” such as the supposedly objective dislike of foreigners and immigrants by the working class.

In the quest to reassert its values, today’s liberalism must be more than either a reflexive anti-Trumpism or a mere defense of a conception of the center based on a false equivalence of left and right populism. In the self-critical spirit espoused by Berlin and others, it must rethink its principles for our time, and let go of the illusion, shared by many post-1989 liberals, that historical progress is predetermined. Cold war liberals believed in the legitimacy of conflict contained by democratic procedures. They regarded conflicts, in Schlesinger’s words, as a guarantee of freedom. But conflicts were not just given, so that centrism meant accommodating both sides a little bit; rather, it took imagination to define conflicts on one’s own terms, while remaining faithful to what Schlesinger called “the spirit of human decency.”