Every day brings more evidence of the United States’ profound political polarization. Partisan intransigence, vitriol, and divisiveness now contaminate most government institutions. What is more, these sentiments have steadily infiltrated every nook and cranny of American life. The 2020 presidential campaign will only further intensify the country’s partisan tribalism. And despite the lofty praise that news media and civil society heap on politicians who work across party lines, the divisive trend continues with no end in sight.

The more than 35 books published on this subject in the past decade have shed much light on partisan dynamics. Yet almost without exception, they examine U.S. polarization as an isolated phenomenon, separate from the experiences of other countries. In our research and advocacy work, we have taken a different tack.

Collaborating with scholars from around the world, we have examined the striking rise of severe polarization in numerous other democracies, including Bangladesh, Colombia, Poland, and Turkey. In each case we took a close look at the roots of polarization and then traced its trajectory over time, analyzing the main drivers as well as the negative consequences and attempted remedies.

Although polarization in the United States shares some basic features with political divisions elsewhere, we found that it stood out in many crucial respects. American polarization has deep roots that have taken decades to grow and strengthen. The United States may look much like many other angry, divided countries, but its brand of polarization raises specific concerns about the future and functioning of its democracy.

WHO KILLED CONSENSUS?

In most highly polarized states, the fundamental divisions arose first among elite political actors. They then spread throughout society when politicians made calculated efforts to solidify or expand their bases. U.S. polarization has altogether different sources. Partisan sentiment bubbled up from the belly of American society, not the head.

The cultural transformations that swept the United States in the 1960s and 1970s first set the trend in motion. During this period, the civil rights movement, the women’s rights movement, the anti–Vietnam War movement, and the sexual revolution all upended established traditions and hierarchies. Two contending visions of America emerged from the maelstrom: a progressive vision that embraced far-reaching sociopolitical change and a conservative vision that sought to block or limit it. Politicians and political parties were slow to use the emerging rift to their advantage. Instead, social activists, evangelists, and public intellectuals drove the rise of polarization within American society.

Only later did polarization worm its way into the formal political realm. As the progressive and conservative social movements gained force and coherence, their ideologues vied for influence within the Democratic and Republican parties, seeking to transform what had for several decades been two catchall, ideologically heterogeneous parties into more defined, programmatic organizations.

Partisan sentiment bubbled up from the belly of American society, not the head.

In most other seriously polarized countries, charismatic leaders were the main contributors to the schism. Not so in the United States. Until recently, there was no American equivalent to President Recep Tayyip Erdogan in Turkey or President Hugo Chávez in Venezuela. In fact, most U.S. presidents in the past four decades have tried to appeal at least somewhat to the center—whether it was Richard Nixon pursuing a raft of relatively moderate socioeconomic policies, Bill Clinton adopting a strategy of “triangulation” after 1994, or George W. Bush trying to advance some elements of “compassionate conservatism.”

Donald Trump is a startling exception in this regard. He is the first U.S. president within living memory to wield polarization as a core political strategy, deliberately seeking to intensify partisan emotions around the most divisive issues facing the country. But his administration is as much a symptom as it is a cause of polarization. In this, Trump is unlike his counterparts in Ankara or Caracas.

To the extent that polarization in the United States comes from the bottom rather than the top, political elites cannot easily reverse or moderate it, even if they genuinely wish to do so. Countries that manage to ease polarization are typically ones where a sharply divisive figure has left the scene and his or her successors are able to walk back the corrosive partisanship. In Ecuador, for instance, President Lenín Moreno has moved away from the antidemocratic tactics of his predecessor, even though the two men come from the same party. In the United States, by contrast, partisanship has continually deepened over the last five decades, regardless of who has occupied the White House. The lesson is clear: Trump’s eventual departure may temper America’s polarization fever, but it will not cure the malady.

POISONED ROOTS

The story of polarization is much longer in the United States than in most democracies. Only a few other countries, such as Argentina and Kenya, have been grappling with severe polarization for more than half a century. Even fewer face polarization that continually intensifies rather than burning out over time. Most current cases of extreme polarization are, at best, 20 years old. (Consider Hungary, Poland, or Venezuela.) Because of its durability, partisanship in the United States has become a characteristic that is passed down across generations, making another kind of political life hard to imagine.

What is more, polarization in the United States is especially multifaceted. In most cases, polarization grows out of one primary identity division—usually either ethnic, religious, or ideological. In Kenya, for instance, polarization feeds off fierce competition between ethnic groups. In India, it reflects the divide between secular and Hindu nationalist visions of the country. But in the United States, all three kinds of division are involved.

The clash that emerged in the 1960s and 1970s between progressive and conservative worldviews had a strong ideological component—especially when compared to the era of “consensus politics” that came immediately before. That said, race was and continues to be a major fault line—one that cannot, and should not, be ignored. And religion matters too: movements in the 1960s and 1970s to legalize abortion, to increase access to birth control, and to ban state-sponsored prayer in public schools brought religion directly into political debates and decisions.

This powerful alignment of ideology, race, and religion with partisanship renders America’s divisions unusually encompassing and profound. It is hard to find another example of polarization in the world that fuses all three major types of identity divisions in a similar way.

A BROKEN SYSTEM

Political life in the United States has some distinct structural features that feed polarization. A two-party system could work against bifurcation if the leading parties are moderate, catch-all parties that compete for the political center. But the United States is unusual in that it has a two-party system dominated by parties that have, in recent decades, become not just more ideological but also quite institutionally weak. (Both parties now use open primaries to choose candidates and rely on more candidate-driven than party-driven political financing than is common in other democracies.) The parties have thus given up most of the tools that would allow them to serve as moderating gatekeepers, both at the national and state levels. More important, the first-past-the-post electoral system is a powerful obstacle to the formation of major third parties that could break up partisan binaries.

Political life in the United States has some distinct structural features that feed polarization.

The record elsewhere shows that two guardrail institutions are crucial in preventing strenuous political competition from veering into destructive polarization—an apolitical judiciary and an independent election administration. While the courts safeguard democracy in many respects, the U.S. judiciary has certain features that undercut its function as a bulwark against polarization. The overtly political process for appointing and confirming Supreme Court justices (as opposed to the more consensus-oriented and depoliticized processes in other major democracies) encourages partisanship. At the state level, some judges are elected with party support—a practice tantamount to letting polarization in through the front door.

When it comes to elections, the United States is one of the few wealthy Western democracies that places elected officials in charge of election administration. The system’s attendant vulnerability to partisanship was on full display in the disputed 2000 presidential election. Fights over voter access highlight the problem today. No other established democracy is still struggling to settle such basic rules about how voting should be carried out. And the weakness of the system as a guardrail against polarization is thrown into even sharper relief now that the United States has a president who repeatedly broadcasts patently false allegations of election fraud.

THE ROAD AHEAD

The barbs of U.S. polarization today are unusually sharp. Thankfully, the United States has many traditions and institutions that help its democracy hold together in the face of the centrifugal pressures: above all, the country has a deep attachment to the rule of law, constitutionalism, and the idea of democracy itself. The same is not true elsewhere. Countries that have descended into severe polarization without some or all of the abovementioned anchors—like Bangladesh, Thailand, and Turkey—have suffered serious blows to their democracies. But not everything that makes the United States politically distinctive works against polarization. And if Americans fail to tackle this issue in the years ahead, tribalism may become an entrenched part of our political system—a tradition as American as apple pie.