Governments described as populist are now in power in Poland, Hungary, Mexico, and Turkey. Italy and Greece are governed by multiparty populist coalitions, while populists of the left or right are partners in coalition governments in seven other European Union countries. Venezuela is in free fall thanks to the confiscationist policies of a populist government. Brazil has an outspoken populist president. And the ongoing Trumpist takeover of the Republican Party isn't just a populist spectacle in itself; it has also helped fuel a surge of left-wing populism among the Democrats. Those movements espouse a variety of programs across a wide range of political landscapes. What do they have in common?

Historians and political scientists have argued for decades about what exactly populism is, and they haven't always come to the same conclusions. The political theorist Isaiah Berlin warned in 1967 that "a single formula to cover all populisms everywhere will not be very helpful. The more embracing the formula, the less descriptive. The more richly descriptive the formula, the more it will exclude." Nonetheless, Berlin identified a core populist idea: the notion that an authentic "true people" have been "damaged by an elite, whether economic, political, or racial, some kind of secret or open enemy."

The exact nature of that enemy—"foreign or native, ethnic or social"—doesn't matter, Berlin adds. What fuels populist politics is that concept of the people battling the elite.

The Princeton political scientist Jan-Werner Müller proposes another characteristic: "In addition to being antielitist, populists are always antipluralist," he argues in 2016's What Is Populism? (University of Pennsylvania Press). "Populists claim that they, and they alone, represent the people." In that formulation, the key to understanding populism is that "the people" does not include all the people. It excludes "the enemies of the people," who may be specified in various ways: foreigners, the press, minorities, financiers, the "1 percent," or others seen as not being "us."

Donald Trump casually expressed that concept while running for president, declaring: "The only important thing is the unification of the people, because the other people don't mean anything." During the Brexit campaign, Nigel Farage, then-leader of the United Kingdom Independence Party, predicted "a victory for real people." Apparently, those who voted against Brexit didn't just lose; they weren't real people to begin with.

Not every formulation of populism looks like that. The historian Walter Nugent, for example, argued in 1963's The Tolerant Populists that America's historical Populist Party was no more anti-pluralist than its opponents. In Populism's Power, released the same year as Müller's book, the Wellesley political scientist Laura Grattan offered a definition of populism that has room for pluralist, inclusive movements. But it is the Berlin-Müller brand of populism that is currently surging in Ankara, Budapest, and Washington, threatening individual liberty, free markets, the rule of law, constitutionalism, the free press, and liberal democracy.

The policies promoted by those governments vary, but they reject two related ideas. One is pluralism, the idea that people are variegated, with different interests and values that need to be negotiated through democratic political processes. The other is liberalism—not in the narrow American sense of the political center-left, but the broader belief that individuals have rights and the state's power should be limited to protect those rights.

Populists can be "of the left," but they need not be motivated by Marxian ideas of class conflict or central planning. They can be "of the right," but they are distinctly different from old-school reactionaries who yearn for a lost world of ordered hierarchies; if anything, they tend to dissolve old-fashioned classes and social orders into the undifferentiated mass of The People. Or they can reject the left/right spectrum altogether. As the French populist leader Marine Le Pen put it in 2015, "Now the split isn't between the left and the right but between the globalists and the patriots."

Populists frequently believe that the true will of the authentic people is focused in one leader. Hugo Chávez, Venezuela's late populist president, put it bluntly: "Chávez is no longer me! Chávez is a people! Chávez—we are millions. You are also Chávez! Venezuelan woman, you are also Chávez! Young Venezuelan, you are Chávez! Venezuelan child, you are Chávez! Venezuelan soldier, you are Chávez! Fisherman, farmer, peasant, merchant! Because Chávez is not me. Chávez is a people!" Turkey's leader, Recep Tayyip Erdoğan, once responded to a lone opposition voice by thundering, "We are the people! Who are you?" And then there's Donald Trump's less dramatic declaration that "I am your voice!"

Populists may seek power by democratic means, but that does not make them liberal. They often campaign against limits on the power of the people, especially independent judiciaries and other checks on the executive. Populists can be socialist or nationalist or both, they can be "pro-business" (crony capitalist) or "pro-labor" (crony unionist), but they share the idea that society must be put under some sort of control, exercised by a leader or a party that represents the true people and is fighting against their enemies.

The Children of Carl Schmitt

Antagonism, thus, is foundational to the populist mentality. And the central theorist of antagonism was Carl Schmitt, a German philosopher of the Nazi era—he is sometimes called the "crown jurist of the Third Reich"—who has had a strong influence on both the hard left and the hard right.

In The Concept of the Political (1932), a relentless critique of classical liberalism and constitutional democracy, Schmitt sought to displace the ideal of voluntary cooperation with the idea of conflict. The "specific political distinction to which political actions and motives can be reduced," Schmitt wrote, "is that between friend and enemy." The contemporary theorists who have taken this notion up include the left-wing populist Chantal Mouffe and her husband, Ernesto Laclau, author of On Populist Reason (2005).

Laclau, whose ideas have influenced populist governments in Greece and Argentina and populist opposition movements across Latin America and Europe, applies Schmittian thinking directly. Indeed, he goes further than Schmitt, treating enmity per se as the very principle of power. Where Schmitt, a virulent anti-Semite, identified the Jews as the perpetual enemy, Laclau's hostility can be directed against anyone.

For Laclau, a populist movement is a collection of otherwise unrelated unmet "demands" aggregated by manipulative populist leaders. The demands are all different, but they are unified in a movement that constitutes "the people." The designation of "the enemy of the people" is a strategic matter, a means of assembling a coalition powerful enough to be united under a leader for the purpose of seizing state power.

The final and most toxic ingredient is "affective investment"—that is, emotional engagement. What unites the otherwise disparate and inchoate demands, Laclau says, is the group's adoration of the leader and hatred of the enemy.

Íñigo Errejón, a leader of the leftist Podemos populist party in Spain and an enthusiastic defender of Venezuela's regime, builds his populism explicitly on the idea that collectivities are created by positing an enemy against which the people must struggle. In his case, the enemy is "the casta, the privileged." When asked who the casta are, Errejón responded: "The term's mobilizing power comes precisely from its lack of definition. It's like asking: Who's the oligarchy? Who's the people? They are statistically undefinable. I think these are the poles with greatest performative capacity."

Mouffe described the choice of target as essential to building the "sort of people we want to build." By identifying The Enemy, The People is constructed.

It's Not the Economy, Stupid

The old standby explanation of populism is that it is a predictable response to economic oppression. Thus, the socialist pundit John Judis argues in 2016's The Populist Explosion: How the Great Recession Transformed American and European Politics that populism rose in response to "the skewed distribution of jobs and income that neoliberal economics had created over the prior decades."

Yet populists have surged in popularity or come to power in countries with very dissimilar economic conditions, including some with low unemployment and relatively high economic growth. Nor is the rise of populism a matter of age, with older people supporting right-wing nationalist populists and younger people supporting liberal cosmopolitanism: Plenty of young people have been voting for populist parties and candidates. Nor is the populist vote explained robustly by income levels.

The British political scientists Roger Eatwell and Matthew Goodwin point out in their 2018 book National Populism: The Revolt Against Liberal Democracy (Pelican) that a common driver in "national populism" is not falling wages but "relative deprivation—a sense that the wider group, whether white Americans or native Brits, is being left behind relative to others in society, while culturally liberal politicians, media and celebrities devote far more attention and status to immigrants, ethnic minorities and other newcomers." Rapid change in the status of groups, notably through immigration, causes many people to experience relative downward mobility and to feel that the status of their group is threatened. When Britain voted to withdraw from the European Union, Eatwell and Goodwin write, polling data showed Remainers "talking endlessly about economic risks while Leavers were chiefly concerned about perceived threats to their identity and national groups." (Brexit is a complex question, of course, and some classical liberals supported it because they feared an unaccountable E.U. bureaucracy. But the movement for Brexit was driven far more by populist concerns than by liberal ones.)

In the U.S., a deciding factor in Trump's victory was the estimated 9 percent of voters who cast ballots for Obama in 2012 and then switched to Trump, according to survey data analyzed by George Washington University political scientist John Sides. Among white Obama voters who had not been to college, the share who later voted for Trump was a whopping 22 percent. As that past support for Obama suggests, their votes for Trump can't be reduced to a simple story of racial backlash. Nor was it a simple matter of economics: For the most part, those voters' incomes and living standards are higher than those of their parents.

But a common motivation for their support for Trump seems to be insecurity about their social status. A 2016 Brookings Institution survey showed that 66 percent of non-college-schooled American whites "agree that discrimination against whites is as big a problem today as discrimination against blacks and other minorities." Anxiety about status—in this case a perception of an inversion of the status quo—seems to be a major factor, certainly much bigger than ideological racism. As political scientist Karen Stenner argued based on extensive data in her 2005 book The Authoritarian Dynamic, threats to "collective rather than individual conditions" trigger authoritarian "groupiness," i.e., populism.

Here's where classical liberals need to do some serious thinking. A mainstay of arguments for free markets is that when people's incomes rise at different rates, the important thing is that they're all rising. Even most left-wing egalitarians accept some inequality, as long as it's necessary for the poor to become less poor. The philosopher John Rawls argued in A Theory of Justice, for instance, that inequalities can be just if they are to the "greatest benefit of the least advantaged," because then, even the least well off could not complain. But human beings are concerned about more than how well they're doing relative to how well they did in the past. They also care about how well they're doing compared to others. They care about hierarchies and social status.

Relative status is quite different from absolute well-being. Libertarians have for many years celebrated the rise in status of women, racial minorities, immigrants, openly gay people, and others who had for very long periods of time suffered from low social status. Well, when it comes to relative social status, if some rose, others had to fall. And who perceived themselves as falling? White men without college degrees.

It isn't just onetime outsiders rising in comparative status. As Charles Murray lays out in his 2012 book Coming Apart: The State of White America, 1960–2010, a decline in our collective emphasis on certain traditional virtues—hard work, marriage, and the like—has opened a gulf between college-schooled elites and high-schooled nonelites. The resentment felt by one side of the divide is, unfortunately, often matched by the arrogance and condescension shown by the other, which merely accentuates the resentment.

Similar divisions are happening in other countries as well, and they seem to be a major driver of populist sentiment. Pew Research Center surveys conducted in 2017 in 15 countries identified ethnocentrism and perceptions of national decline as characteristic of populist voters. In Germany, for example, 44 percent of the populist Alternative for Germany (AfD) party's supporters say that life is worse than it was 50 years ago for people like them, compared to only 16 percent of other Germans. While data vary across countries and, as Berlin pointed out in 1967, no one factor can explain all populist movements, such fears of national decline and group status are common, especially in Europe and the U.S. The most important driver in Europe and the U.S. seems to be immigration and what Eatwell and Goodwin in National Populism call "hyper ethnic change"—that is, rapid change in the ethnic mix of a society, with multiple ethnicities joining the social order. (Some Americans have experienced feelings of dislocation and threat to their place in society upon seeing that their old Piggly Wiggly store has been replaced by a mercado with Mexican flags. It's not the experience of ethnic pluralism that seems to be the problem but the fear that other ethnicities will eventually displace them.)

The percentage of U.S. residents who were foreign-born reached 13.7 percent in 2017, the highest percentage since 1910, when it was 14.7 percent. Moreover, since the Immigration and Naturalization Act of 1965, which abolished national quotas and favored family reunions, higher percentages of immigrants have been coming from Asia, Africa, Central America, and the Middle East, accentuating ethnic differences with the native-born population.

The Alternative for Germany, which started as a movement against the euro and has morphed into a populist anti-immigrant party, has drawn increasing support from less-schooled voters from the former states of East Germany. Such voters perceive their status as having fallen in recent decades, and they fear immigration far more than do more-schooled voters and those in the Western part of the country, which has seen far more immigration. In fact, the AfD support was strongest in those regions of the East that had seen the least population growth due to migration; people in those places feel that they are being left behind, and they blame immigrants, whom they see more on television than in their neighborhoods.

Similar analyses can be applied to Britain, France, Sweden, and other democracies that have seen surges of populism.

Hyper ethnic change is profoundly unsettling to many people, and it is helping to drive populist political responses. One can dismiss such reactions as irrational or small-minded, but many people feel them nonetheless. Moreover, many people are not satisfied with improvements in their conditions if they perceive others—especially outsiders—as doing even better. Envy and resentment have long been drivers of anti-libertarian movements, and they seem to be back in a big way. The problem is exacerbated by the increase of welfare-state transfer payments and benefits, which outsiders are believed to exploit or threaten.

I fear that we may be entering an age of authoritarian "groupiness" and that the consequences will be terrible for freedom and prosperity. Not to put too fine a point on it, but the rise of far-right and far-left authoritarian populist movements today is more than a little reminiscent of Europe in the 1930s.

The Libertarian Response

To take on such populist ideas, we must start by understanding them. If fear regarding immigration trends is driving a larger fear of liberal democratic capitalism, one response is to ensure that immigration procedures are (accurately) perceived as orderly rather than as invasive. Attitudes toward both the Syrian refugees fleeing a catastrophic war and the current situation on the United States' southern border have arguably been shaped for the worse by a failure to fashion more systematic and orderly solutions, entailing a right to work legally, for example.

The reason so many people choose to cross into the U.S. illegally, and in risky ways, is that it's extraordinarily difficult to obtain a visa at an American consulate and travel by bus or car through a legal port of entry. Those who enter without permission or overstay their visas are less likely to go home, as was previously common, when they are not sure they'll be able to return to work again in the future. A functioning and efficient guest worker program—one that allows people to easily take temporary jobs in the United States and then return home to their families with the wealth they've rightfully acquired—could help calm the worries of American citizens who balk at the idea that throngs of foreigners are forcing their way across the border.

But is there anything libertarians, the vast majority of whom remain outside the halls of power where immigration policy is set, can do?

One idea is to push back against the idea that trade is a zero-sum game. Your benefit need not come at my expense. What is good for Germany can be good for France, if Germans and Frenchmen trade goods and services rather than bullets and bombs. Immigrants who arrive to work enrich the people among whom they work. Negative-sum games can be transformed into positive-sum games by establishing the right institutions: property, contract, and voluntary trade. Trade has improved the well-being of Americans, of Germans, of Kenyans, of everyone.

Libertarians also need to take a hard look at our own rhetoric. Trying to divide humanity into taxpayers and tax eaters, as if there were some easy way in a modern society to distinguish the two groups neatly and unambiguously, feeds into populist hatred and rage. By all means cut subsidies, but demonizing the recipients as enemies of the people, as mere parasites, contributes to a climate of resentment, hatred, revenge, and conflict that undermines the framework for peaceful, voluntary cooperation on which liberty rests.

Thinking about the world in terms of friends vs. enemies channels energy into collectivism and demagoguery. To stop authoritarian populism, it's important not to promote the mentality of enmity that enables it.