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Why Has America Become So Divided?

Four reasons the United States doesn’t seem so united anymore.

“We weaken our greatness when we confuse our patriotism with tribal rivalries that have sown resentment and hatred and violence in all the corners of the globe. We weaken it when we hide behind walls, rather than tear them down, when we doubt the power of our ideals, rather than trust them to be the great force for change they have always been.”
— Senator John McCain (2018)

"There is no monopoly of common sense
On either side of the political fence
We share the same biology
Regardless of ideology
Believe me when I say to you
I hope the Russians love their children too."
Russians, Sting (1985)

Public domain
Cain and Abel, Titian (circa 1543)
Source: Public domain

For many of us these days, it feels as if the United States has never been less united. The nation, it seems, has become irrevocably fractured along political and ideological lines — Republican/Democrat, liberal/conservative, red/blue, etc. Sitting down for Thanksgiving dinner with family has never been more uncomfortable and the admonition to avoid discussing religion or politics in polite company has never been more apropos.

What has happened to America? And how can we reverse the trend?

A Matter of Perspective

First, we need to examine whether the country is divided or merely seems that way. Several articles have been written over the past few years reminding us that, despite the name, the US been divided for much of its existence (see Jonathan Rauch’s article at Brookings and Scotty Hendricks’ at Big Think). Indeed, it would be hard to argue that the country is more divided now than it was during the Civil War and in fact, the familiar proscription against discussing politics and religion in general company appeared at least as far back as a book of etiquette entitled Hill’s Manual of Social and Business Forms published in 1879. And it could certainly be said that our current political unrest has nothing on the 1960s. Consequently, part of today’s apparent divisiveness appears to be a matter of short-sighted perspective — many of us who feel that the nation has never been so split have only been politically conscious for a few decades and therefore have a narrow timeline from which to compare.

Ideologues Without Issues

Still, there is good evidence that American political parties have become increasingly polarized over the past several decades, with Democratic and Republican politicians disagreeing over policy more than ever. Witness the headlines following the death of Senator John McCain last week — “John McCain and the Dying Art of Political Compromise” in the Wall Street Journal and “McCain’s Death Marks the Near-Extinction of Bipartisanship” at NPR. But what’s less clear is whether political party division reflects division within the general public and American culture at large. Suffice it to say that the evidence is… well, somewhat divided.

A 2017 PEW Research Center poll of 5,000 US adults reported that partisan divide over political issues related to racial discrimination, immigration, international diplomacy, and government aid to the needy has indeed widened significantly since the early 1990s.1 There was an average 36% difference of opinion on these issues (up from just 15% in 1994) across party lines — based on those identifying as or “leaning” to either Democrats or Republicans. This gap dwarfed divisions across differences in age, gender, race, education, and church attendance. These results indicate that for those who affiliate with a political party, polarization over “the issues” does seem to have increased over the past 20 or 30 years.

But a 2012 study by Stanford University political science professor Shanto Iyengar and colleagues offers another way of looking at this apparent split.2 It examined political polarization from a different angle — not from how Americans stand on policy issues, but from the perspective of “affect” — how they feel about those on the other side of the political fence. Drawing from survey data spanning several decades, the study found that the feelings of those who affiliate as Democrat or Republican towards members of the opposing party have become increasingly negative since the late '80s. The general pattern of dislike was mirrored by other specific metrics of “social distance” — disapproval of one’s child marrying someone from the opposing party as well as the attribution of negative stereotypes (e.g. close-minded, hypocritical, selfish, mean) to those of the opposing party, both of which have increased sharply since the '60s. Curiously, this “affect polarization” wasn’t so much related to ideology (i.e. where one stood on political issues) as much as partisan identity per se.

In a more recent study published just this year entitled “Ideologues Without Issues: The Polarizing Consequences of Ideological Identities,” University of Maryland professor Lilliana Mason extended Iyengar’s findings by distinguishing between two separate aspects of political ideology — “issue-based” (defined by what one believes about the issues) and “identity-based” (defined by one’s social identity of party affiliation).3 In Dr. Mason’s examination of political survey data, by far the more potent predictor of social distance was identity-based ideology — how we identify ourselves as Democrats or liberals as opposed to Republicans or conservatives — not where we stand on the issues.

Collectively, these results indicate that it’s the social identifying role of ideological affiliation that’s paramount in guiding our negative emotional responses to those on the other side of the political fence. This conclusion helps us to understand a few seemingly puzzling aspects of politics today — for example, how politicians can “pivot” on the issues when running for office and how key components of traditional party platforms can sometimes turn on a dime (e.g. the GOP and Russia), and why hypocrisy seems to run rampant in politics today. For much of the voting public, political affiliation isn’t so much about the issues as it is about being part of “Team Red” and “Team Blue.” So opposed between “us” and “them,” “liberals become “libtards,” “conservatives” become “fascists,” and the possibility of finding common ground flies out the window. As NYU philosophy professor Kwame Anthony Appiah recently put it, “all politics is identity politics.”

The Enemy of the People?

On its own, the conclusion that we’re “ideologues without issues” doesn’t explain why political polarization has increased over the past several decades. But Dr. Iyengar’s study supplies a clue with the additional finding that increasing affect polarization was correlated with increasingly negative political campaigning over time.2 Noting the relationship between negative campaigning and press coverage, the study authors wrote that “negative (but not positive) messages are recycled ad infinitum by journalists who seek conflict and controversy above all else” and that “technology has facilitated citizens’ ability to seek out information sources they find agreeable and tune out others that prove dissonant.” In other words, campaign muckraking appears to increase affect polarization, while press coverage of that conflict fans the flame of confirmation bias.

Confirmation bias is to belief formation as “location, location, location” is to real estate — it’s one of the most powerful determinants, if not the most powerful determinant, of how we consolidate beliefs when consuming information. This is a well-tread theme here in Psych Unseen (see my previous blogs on about forming beliefs based on online information “Fake News, Echo Chambers, & Filter Bubbles: A Survival Guide” and “Psychology, Gullibility, and the Business of Fake News”). Over the past several decades, the proliferation of cable news networks and options for online information, the increased intermingling of opinion and news, and a “click-based” revenue model that incentivizes sensationalism has resulted in a kind of “confirmation bias on steroids” for informational consumers. With Republicans relying on Fox News and Democrats on the likes of The Daily Show as the go-tos for their political news, no wonder disdain for members of the opposing party has run wild.

Another study published earlier this year by Texas Tech University professor Bryan McLaughlin provides additional insight regarding the contributing role of the media in the political polarization of the country.4 In this survey-based study, Dr. McLaughlin exposed a national sample of Democrats and Republicans to a fabricated news story covering the results of a 2013 Pew Research Study. The poll results were manipulated to expose subjects to two different story versions that either emphasized or de-emphasized US political polarization, with a third control condition that involved no exposure to any story. Those who watched the news story that emphasized political polarization reported a subsequent increase in the perception of conflict as well as a measure of affect polarization that combined in-group favoritism and social distance. The perception of conflict in turn mediated effects on increasing partisan identification (affiliating with Democrat or Republican) and ideological polarization (affiliating as liberal or conservative). These novel findings suggest that when partisans are exposed to news about political conflict, they tend to circle their ideological wagons and steel themselves against seeing eye to eye. Objective news reporting is the antithesis of “the enemy of the people,” but selective exposure to politically-biased news and news in general that highlights political conflict can fuel the fire of political polarization in what amounts to a vicious cycle.

It’s the Russians, Stupid

No discussion of modern political polarization is complete without mention of the contribution of Russian trolls and bots to fomenting American dissatisfaction with life in a multicultural democracy. It’s now well-established that Russia attempted to influence the results of the 2016 US Presidential Election though the propagation of online misinformation, though of course whether it did influence the election and to what extent collusion occurred and by whom remains a matter of partisan debate. Just this past month, a study was published the found that Russian bots on Twitter have also been weighing in on the debate over vaccines, with bots significantly more likely to Tweet about vaccines in general, with both pro- and anti-vaccination messages, than the average Twitter user.5 This finding is consistent with the theory that the intent of Russian trolls operating under the political direction of the Kremlin is to sow the seeds of American discord.

Coupled with Dr. McLaughlin’s finding that being exposed to apparent evidence of political polarization (regardless of reality) increases political polarization, it can be rightly said that reporting about polarization has the potential to be used as a political weapon. And yet, news of Russian influence on American polarization reminds us that we may not be as irreconcilably divided as it might seem from our online interactions.

Can the United States Become More United Again?

If there is hope for Americans to move forward together as a country, it lies in the promise that democracy can bring those from different cultures and disparate viewpoints to the same table where they can work collaboratively based on a larger shared identity and the greater common good. Much of what we know, or think we know, about political polarization is based on polls and surveys that force respondents into dichotomous choices that may fail to capture the complexity of how people actually feel. In reality, many partisans have more nuanced views than one might assume, just as apparent “moderates” might have extreme opinions that are inconsistent with a unified party platform and therefore "cancel each other out" (e.g. “conservatives” who are “pro-choice”).6

In around 2016, Ken Stern, former NPR CEO and author of Republican Like Me: How I Left the Liberal Bubble and Learned to Love the Right, set out across the country and “went to evangelical churches, shot a hog in Texas, stood in pit row at a NASCAR race, and hung out at Tea Party meetings” in order to better understand “conservative America.” What he found, based on face-to-face interactions, was that “Americans aren’t as divided as you think.” Although he encountered some “less than attractive types along the way,” he was “almost always able to find more points of agreement and commonality than I thought was possible.”

The anecdotal nature of Mr. Stern’s road trip and criticisms of his “cultural tourism” as a white male aside, his experience highlights the possibility that political partisans can indeed find common ground when it is sought during in-person interactions that occur outside of social media and focus on issues as opposed to bashing politicians. If that's the case, then American political polarization may not be as irreversible as it might seem. At the end of his journey, Mr. Stern denounced his Democratic affiliation and became an independent voter. Given what we’ve learned about affect polarization being mediated by social identity, perhaps more Democrats and Republicans should follow his lead.

For more on the psychology of a divided America:

Can Polarized American Politics Find the Middle Way?


1. Pew Research Center, “The Partisan Divide of Political Values Grows Even Wider.” October 5, 2017.

2. Iyengar S, Sood G, Lelkes Y. Affect: not ideology: a social identity perspective on polarization. Public Opinion Quarterly 2012, 76: 405-431.

3. Mason L. Ideologues without issues: the polarizing consequences of ideological identities. Public Opinion Quarterly 2018, 82: 280-301.

4. McLaughlin B. Commitment to the team: perceived conflict and political polarization. Journal of Media Psychology 2018; 30:41-51.

5. Broniatowski DA, Jamison AM, Qi S, et al. Weaponized health communication: Twitter bots and Russian trolls amplify the vaccine debate. Research and Practice, August 18, 2018.

6. Broockman DE. Approaches to studying policy representation. Legislative Studies Quarterly 2016; 41:181-214.

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