Humans, like other primates, are tribal animals. We need to belong to groups, which is why we love clubs and teams. Once people connect with a group, their identities can become powerfully bound to it. They will seek to benefit members of their group even when they gain nothing personally. They will penalize outsiders, seemingly gratuitously. They will sacrifice, and even kill and die, for their group.

This may seem like common sense. And yet the power of tribalism rarely factors into high-level discussions of politics and international affairs, especially in the United States. In seeking to explain global politics, U.S. analysts and policymakers usually focus on the role of ideology and economics and tend to see nation-states as the most important units of organization. In doing so, they underestimate the role that group identification plays in shaping human behavior. They also overlook the fact that, in many places, the identities that matter most—the ones people will lay down their lives for—are not national but ethnic, regional, religious, sectarian, or clan-based. A recurring failure to grasp this truth has contributed to some of the worst debacles of U.S. foreign policy in the past 50 years: most obviously in Afghanistan and Iraq, but also in Vietnam.

This blindness to the power of tribalism affects not only how Americans see the rest of the world but also how they understand their own society. It’s easy for people in developed countries, especially cosmopolitan elites, to imagine that they live in a post-tribal world. The very term “tribe” seems to denote something primitive and backward, far removed from the sophistication of the West, where people have supposedly shed atavistic impulses in favor of capitalistic individualism and democratic citizenship. But tribalism remains a powerful force everywhere; indeed, in recent years, it has begun to tear at the fabric of liberal democracies in the developed world, and even at the postwar liberal international order. To truly understand today’s world and where it is heading, one must acknowledge the power of tribalism. Failing to do so will only make it stronger.

basic instinct

The human instinct to identify with a group is almost certainly hard-wired, and experimental evidence has repeatedly confirmed how early in life it presents itself. In one recent study, a team of psychology researchers randomly assigned a group of children between the ages of four and six to either a red group or a blue one and asked them to put on T-shirts of the corresponding color. They were then shown edited computer images of other children, half of whom appeared to be wearing red T-shirts and half of whom appeared to wearing blue, and asked for their reactions. Even though they knew absolutely nothing about the children in the photos, the subjects consistently reported that they liked the children who appeared to be members of their own group better, chose to hypothetically allocate more resources to them, and displayed strong subconscious preferences for them. In addition, when told stories about the children in the photos, these boys and girls exhibited systematic memory distortion, tending to remember the positive actions of in-group members and the negative actions of out-group members. Without “any supporting social information whatsoever,” the researchers concluded, the children’s perception of other kids was “pervasively distorted by mere membership in a social group.”

Seeing group members prosper seems to activate our brains’ “reward centers” even if we receive no benefit ourselves.

Neurological studies confirm that group identity can even produce physical sensations of satisfaction. Seeing group members prosper seems to activate our brains’ “reward centers” even if we receive no benefit ourselves. Under certain circumstances, our reward centers can also be activated when we see members of an out-group failing or suffering. Mina Cikara, a psychologist who runs Harvard’s Intergroup Neuroscience Lab, has noted that this is especially true when one group fears or envies another—when, for example, “there’s a long history of rivalry and not liking each other.”

This is the dark side of the tribal instinct. Group bonding, the neuroscientist Ian Robertson has written, increases oxytocin levels, which spurs “a greater tendency to demonize and de-humanize the out-group” and which physiologically “anesthetizes” the empathy one might otherwise feel for a suffering person. Such effects appear early in life. Consider two recent studies about the in-group and out-group attitudes of Arab and Jewish children in Israel. In the first, Jewish children were asked to draw both a “typical Jewish” man and a “typical Arab” man. The researchers found that even among Jewish preschoolers, Arabs were portrayed more negatively and as “significantly more aggressive” than Jews. In the second study, Arab high school students in Israel were asked for their reactions to fictitious incidents involving the accidental death (unrelated to war or intercommunal violence) of either an Arab or a Jewish child—for example, a death caused by electrocution or a biking accident. More than 60 percent of the subjects expressed sadness about the death of the Arab child, whereas only five percent expressed sadness about the death of the Jewish child. Indeed, almost 70 percent said they felt “happy” or “very happy” about the Jewish child’s death.

identity over ideology

Insight into the potency of group identity has rarely shaped elite American opinion on international affairs. U.S. policymakers tend to view the world in terms of territorial nation-states engaged in political or ideological struggle: capitalism versus communism, democracy versus authoritarianism, “the free world” versus “the axis of evil.” Such thinking often blinds them to the power of more primal group identities—a blindness that has repeatedly led Washington into blunders overseas.

The Vietnam War was arguably the most humiliating military defeat in U.S. history. To many observers at the time, it seemed unthinkable that a superpower could lose to what U.S. President Lyndon Johnson called “a piddling, pissant little country”—or, more accurately, to half of that country. It’s now well known that U.S. policymakers, viewing Vietnam through a strictly Cold War lens, underestimated the extent to which Vietnamese people in both the North and the South were motivated by a quest for national independence, as opposed to an ideological commitment to Marxism. But even today, most Americans don’t understand the ethnic dimension of Vietnamese nationalism.

U.S. policymakers saw North Vietnam’s communist regime as China’s pawn—merely “a stalking horse for Beijing in Southeast Asia,” as the military expert Jeffrey Record put it. This was a mistake of staggering proportions. Hanoi accepted military and economic support from Beijing, but it was mostly an alliance of convenience. After all, for over a thousand years, most Vietnamese people had feared and hated China. Every Vietnamese child learned of the heroic exploits of his or her ancestors who had fought and died to free their country from China, which conquered Vietnam in 111 BC and then colonized it for a millennium. In 1997, Robert McNamara, who had served as U.S. secretary of defense during the Vietnam War, met Nguyen Co Thach, the former foreign minister of Vietnam. “Mr. McNamara,” he later recalled Thach saying,

You must never have read a history book. If you’d had, you’d know we weren’t pawns of the Chinese. . . . Don’t you understand that we have been fighting the Chinese for 1,000 years? We were fighting for our independence. And we would fight to the last man. . . . And no amount of bombing, no amount of U.S. pressure would ever have stopped us.

Indeed, just a few years after U.S. forces withdrew from Vietnam, the country was at war with China.

Washington also missed another ethnic dimension of the conflict. Vietnam had a “market-dominant minority,” a term I coined in 2003 to describe outsider ethnic minorities that hold vastly disproportionate amounts of a nation’s wealth. In Vietnam, a deeply resented Chinese minority known as the Hoa made up just one percent of the population but historically controlled as much as 80 percent of the country’s commerce and industry. In other words, most of Vietnam’s capitalists were not ethnic Vietnamese. Rather, they were members of the despised Hoa—a fact that Vietnam’s communist leaders deliberately played up and exaggerated, claiming that “ethnic Chinese control 100 percent of South Vietnam’s domestic wholesale trade” and calling Cholon, an area with a predominantly ethnic Chinese population, “the capitalist heart beating within socialist Vietnam’s body.”

A man reaches up to touch a name upon the Vietnam Veterans Memorial in Washington U.S., November 10, 2017. Kevin Lamarque / Reuters

Because U.S. policymakers completely missed the ethnic side of the conflict, they failed to see that virtually every pro-capitalist step they took in Vietnam helped turn the local population against the United States. Washington’s wartime policies intensified the wealth and power of the ethnic Chinese minority, who, as middlemen, handled most of the U.S. military’s supplies, provisions, and logistics (as well as Vietnam’s brothels and black markets). In effect, the regimes that Washington installed in Saigon were asking the South Vietnamese to fight and die—and kill their northern brethren—in order to keep the ethnic Chinese rich. If the United States had actively wanted to undermine its own objectives, it could hardly have come up with a better formula.

pashtun power

Blunders of the sort that Washington made in Vietnam are part of a pattern in U.S. foreign policy. After the 9/11 attacks, the United States sent troops to Afghanistan to root out al Qaeda and overthrow the Taliban. Washington viewed its mission entirely through the lens of “the war on terror,” fixating on the role of Islamic fundamentalism—and yet again missing the central importance of ethnic identity.

Afghanistan is home to a complex web of ethnic and tribal groups with a long history of rivalry and mutual animosity. For more than 200 years, the largest ethnic group, the Pashtuns, dominated the country. But the fall of the country’s Pashtun monarchy in 1973, the 1979 Soviet invasion, and the subsequent years of civil war upended Pashtun dominance. In 1992, a coalition controlled by ethnic Tajiks and Uzbeks seized control.

A few years later, the Taliban emerged against this background. The Taliban is not only an Islamist movement but also an ethnic movement. Pashtuns founded the group, lead it, and make up the vast majority of its members. Threats to Pashtun dominance spurred the Taliban’s ascent and have given the group its staying power.

A Pashtun demonstrator jumps on a burning effigy of British Prime Minister Tony Blair after a peaceful gathering in Peshawar, Pakistan, on October 12, 2001. Adrees Latif / Reuters

U.S. policymakers and strategists paid almost no attention to these ethnic realities. In October 2001, when the United States invaded and toppled the Taliban government in just 75 days, it joined forces with the Northern Alliance, led by Tajik and Uzbek warlords and widely viewed as anti-Pashtun. The Americans then set up a government that many Pashtuns believed marginalized them. Although Hamid Karzai, whom Washington handpicked to lead Afghanistan, was a Pashtun, Tajiks headed most of the key ministries in his government. In the new, U.S.-supported Afghan National Army, Tajiks made up 70 percent of the army’s battalion commanders, even though only 27 percent of Afghans are Tajik. As Tajiks appeared to grow wealthy while U.S. air strikes pounded predominantly Pashtun regions, a bitter saying spread among Afghan Pashtuns: “They get the dollars, and we get the bullets.” Although many Pashtuns loathed the Taliban, few were willing to support a government they viewed as subordinating their interests to those of their deeply resented ethnic rivals.

Seventeen years after the United States invaded Afghanistan, the Taliban still controls large parts of the country, and the longest war in American history drags on. Today, many American academics and policy elites are aware of the ethnic complexities of Afghanistan. Unfortunately, this recognition of the centrality of group identity came far too late, and it still fails to meaningfully inform U.S. policy.

stuff happens

Underestimating the political power of group identity also helped doom the U.S. war in Iraq. The architects and supporters of the 2003 U.S. invasion failed to see (or actively minimized) the depth of the divisions among Iraq’s Shiites, Sunnis, and Kurds, as well as the central importance of tribal and clan loyalties in Iraqi society. They also missed something much more specific: the existence of a market-dominant minority.

Sunnis had dominated Iraq for centuries, first under Ottoman rule, then under the British, who governed indirectly through Sunni elites, and then, most egregiously, under Saddam Hussein, who was himself a Sunni. Saddam favored Sunnis, especially those who belonged to his own clan, and ruthlessly persecuted the country’s Shiites and Kurds. On the eve of the U.S. invasion, the roughly 15 percent of Iraqis who were Sunni Arabs dominated the country economically, politically, and militarily. By contrast, Shiites composed the vast majority of the country’s urban and rural poor.

The result of the surge of U.S. forces into Iraq in 2007 provides evidence that had Washington been more attentive to the importance of group identities in Iraq, the initial invasion and occupation could have turned out very differently.

At the time, a small number of critics (including me) warned that under these conditions, rapid democratization in Iraq could be profoundly destabilizing. In 2003, I cautioned that elections could well produce not a unified Iraq but a vengeful Shiite-dominated government that would exclude and retaliate against Sunnis, an outcome that would further fuel the rise of intensely anti-American fundamentalist movements. Unfortunately, that precise scenario unfolded: instead of bringing peace and prosperity to Iraq, democracy led to sectarian warfare, eventually giving rise to the so-called Islamic State (also known as ISIS), an extremist Sunni movement as devoted to killing Shiite “apostates” as it is to killing Western “infidels.”

The result of the surge of U.S. forces into Iraq in 2007 provides evidence that had Washington been more attentive to the importance of group identities in Iraq, the initial invasion and occupation could have turned out very differently. The influx of 20,000 additional troops was important, but the surge helped stabilize Iraq only because it was accompanied by a 180-degree shift in the U.S. approach to the local population. For the first time during the Iraq war, the U.S. military educated itself about the country’s complex sectarian and ethnic dynamics—recognizing, in the words of U.S. Brigadier General John Allen, that “tribal society makes up the tectonic plates in Iraq on which everything rests.” By forging alliances between Shiite and Sunni sheiks and by pitting moderates against extremists, the U.S. military achieved dramatic successes, including a precipitous decline in sectarian violence and in casualties among Iraqis and U.S. troops alike.

the trump tribe

Vietnam, Afghanistan, and Iraq may seem worlds away from the United States, but Americans are not immune to the forces of tribal politics that have ravaged those countries. Americans tend to think of democracy as a unifying force. But as Iraq has illustrated, and as Americans are now learning firsthand, democracy under certain conditions can actually catalyze group conflict. In recent years, the United States has begun to display destructive political dynamics much more typical of developing and non-Western countries: the rise of ethnonationalist movements, eroding trust in institutions and electoral outcomes, hate-mongering demagoguery, a popular backlash against both “the establishment” and outsider minorities, and, above all, the transformation of democracy into an engine of zero-sum political tribalism.

These developments are due in part to a massive demographic transformation. For the first time in U.S. history, whites are on the verge of losing their status as the country’s majority. To varying degrees, minorities in the United States have long felt vulnerable and under threat; today, whites also feel that way. A 2011 study showed that more than half of white Americans believe that “whites have replaced blacks as the ‘primary victims of discrimination.’” When groups feel threatened, they retreat into tribalism. They close ranks and become more insular, more defensive, more focused on us versus them. In the case of the shrinking white majority, these reactions have combined into a backlash, raising tensions in an already polarized social climate in which every group—whites, blacks, Latinos, and Asians; Christians, Jews, and Muslims; straight people and gay people; liberals and conservatives; men and women—feels attacked, bullied, persecuted, and discriminated against.

But there’s another reason these new tribalistic pathologies are emerging today. Historically, the United States has never had a market-dominant minority. On the contrary, for most of its history, the country has been dominated economically, politically, and culturally by a relatively unified white majority—a stable, if invidious, state of affairs.

But in recent years, something has changed. Owing in part to record levels of economic inequality and to stark declines in geographic and social mobility, white Americans are now more intensely split along class lines than they have been in generations. As a result, the United States may be seeing the emergence of its own version of a market-dominant minority: the much-discussed group often referred to as “coastal elites.” To be sure, “coastal elites” is a misleading term—a caricature, in some ways. The group’s members are neither all coastal nor all elite, at least in the sense of being wealthy. Still, with some important caveats, American coastal elites bear a strong resemblance to the market-dominant minorities of the developing world. Wealth in the United States is concentrated in the hands of a relatively small number of people, most of whom live on the coasts. This minority dominates key sectors of the economy, including Wall Street, the media, and Silicon Valley. Although coastal elites do not belong to any one ethnicity, they are culturally distinct, often sharing cosmopolitan values such as secularism, multiculturalism, toleration of sexual minorities, and pro-immigrant and progressive politics. Like other market-dominant minorities, U.S. coastal elites are extremely insular, interacting and intermarrying primarily among themselves, living in the same communities, and attending the same schools. Moreover, they are viewed by many middle Americans as indifferent or even hostile to the country’s interests.

What happened in the 2016 U.S. presidential election is exactly what I would have predicted would happen in a developing country holding elections in the presence of a deeply resented market-dominant minority: the rise of a populist movement in which demagogic voices called on “real” Americans to, in Donald Trump’s words, “take our country back.” Of course, unlike most backlashes against market-dominant minorities in the developing world, Trump’s populism is not anti-rich. On the contrary, Trump himself is a self-proclaimed billionaire, leading many to wonder how he could have “conned” his antiestablishment base into supporting a member of the superrich whose policies will make the superrich even richer.

In terms of taste, sensibilities, and values, Trump is actually similar to some members of the white working class.

The answer lies in tribalism. For some, Trump’s appeal is racial: as a candidate and as president, Trump has made many statements that either explicitly or in a coded fashion appeal to some white voters’ racial biases. But that’s not the whole picture. In terms of taste, sensibilities, and values, Trump is actually similar to some members of the white working class. The tribal instinct is all about identification, and many voters in Trump’s base identify with him at a gut level. They identify with the way he talks and the way he dresses. They identify with the way he shoots from the hip—even (perhaps especially) when he gets caught making mistakes, exaggerating, or lying. And they identify with the way he comes under attack by liberal commentators—coastal elites, for the most part—for not being politically correct, for not being feminist enough, for not reading enough books, and for gorging on fast food.

In the United States, being antiestablishment is not the same as being anti-rich. The country’s have-nots don’t hate wealth: many of them want it, or want their children to have a shot at it, even if they think the system is rigged against them. Poor, working-class, and middle-class Americans of all ethnicities hunger for the old-fashioned American dream. When the American dream eludes them—even when it mocks them—they would sooner turn on the establishment, or on the law, or on immigrants and other outsiders, or even on reason, than turn on the dream itself.

stemming the tribal tide

Political tribalism is fracturing the United States, transforming the country into a place where people from one tribe see others not just as the opposition but also as immoral, evil, and un-American. If a way out exists, it will have to address both economics and culture.

For tens of millions of working-class Americans, the traditional paths to wealth and success have been cut off. The economist Raj Chetty has shown that during the past 50 years, an American child’s chances of outearning his or her parents have fallen from roughly 90 percent to 50 percent. A recent study published by the Pew Charitable Trusts found that “43 percent of Americans raised at the bottom of the income ladder remain stuck there as adults, and 70 percent never make it to the middle.” Moreover, to an extent that American elites may not realize, their own status has become hereditary. More than ever before, achieving wealth in the United States requires an elite education and social capital, and most lower-income families can’t compete in those areas.

Political tribalism thrives under conditions of economic insecurity and lack of opportunity. For hundreds of years, economic opportunity and upward mobility helped the United States integrate vastly different peoples more successfully than any other nation. The collapse of upward mobility in the United States should be viewed as a national emergency.

But U.S. citizens will also need to collectively fashion a national identity capable of resonating with and holding together Americans of all sorts—old and young, immigrant and native born, urban and rural, rich and poor, descendants of slaves as well as descendants of slave owners. A first step would be to start bridging the chasm of mutual ignorance and disdain separating the coasts and the heartland. One idea would be a public service program that would encourage or require young Americans to spend a year after high school in another community, far from their own, not “helping” members of another group but interacting with people with whom they would normally never cross paths, ideally working together toward a common end.

Increasing tribalism is not only an American problem, however. Variants of intolerant tribal populism are erupting all across Europe, eroding support for supranational entities such as the European Union and even threatening the liberal international order. Brexit, for example, was a populist backlash against elites in London and Brussels perceived by many as controlling the United Kingdom from afar and being out of touch with “real” Britons—the “true owners” of the land, many of whom see immigrants as a threat. Internationally, as in the United States, unity will come not by default but only through hard work, courageous leadership, and collective will. Cosmopolitan elites can do their part by acknowledging that they themselves are part of a highly exclusionary and judgmental tribe, often more tolerant of difference in principle than in practice, inadvertently contributing to rancor and division.