Volume 16, Issue 1

An emerging narrative contends that 2016 was significant for bridging identity politics and American party conflict. This narrative misses a fundamental truth: for ordinary Americans, partisan identity has always been grounded in their orientations toward groups in society. The group theory of parties holds that citizens evaluate political parties according to their social stereotypes of Democrats and Republicans, ultimately identifying (or not) with a party that jives with their own self-image. In this essay, I review existing research and summarize several original studies suggesting that citizens’ beliefs about party composition affect their feelings toward Democrats and Republicans. Americans tend to hold shockingly erroneous beliefs about the degree to which stereotypical groups compose the parties – for example, that 38% of Republicans belong to the economic “1%” – and correcting social stereotypes about the out-party reduces polarization between rank-and-file party supporters. Most studies discussed in this essay were conducted before Donald Trump became a candidate, suggesting that 2016 was not the year that identity politics hijacked the parties, but rather the year in which the implicit group basis for mass partisanship became baldly explicit.

Partisanship continues to divide Americans. Using data from the American National Election Study, as well as implicit attitude tests, we argue that Americans’ partisan identity has become highly salient. Partisans have become more negative towards the opposing party on both explicit and implicit measures, and these biases spill over into their everyday decisions. Partisanship has become one of Americans’ most salient social identities.

The alignment between partisan and other social identities has generated a rift between Democrats and Republicans that is deeper than any seen in recent American history. Without the cross-cutting identities that have traditionally stabilized the American two-party system, partisans in the American electorate are now seeing each other through prejudiced and intolerant eyes. In this article, partisan social divisions are examined in the 2016 electorate, with an eye to the co-occurrence between these social divisions and contemporaneous resistance to compromise and intolerance of social outgroups. In particular, as Republicans and Democrats grow more socially distinct, they like outgroups less and privilege victory over the national greater good. This effect is particularly visible among Republicans, whose social makeup is particularly homogeneous, even in comparison with Democrats. Some potential solutions are briefly addressed.

American partisans are far more hostile towards out-party members than they were 40 years ago. While this phenomenon, often called affective polarization, is well-documented, political scientists disagree on its cause. One group of scholars believes that affective polarization is driven by processes related to social identity theory. In particular, cross-cutting identities have declined in America, and toxic political communication continuously primes partisan identities and resentment. Recently, several scholars have pointed to another phenomenon as the root cause of affective polarization: partisan sorting, i.e. the alignment of partisan identities with ideologically consistent issue positions. I review evidence in favor of each claim, and provide additional evidence that affective polarization has increased about as much among those who are not sorted as among those who are sorted. Furthermore, while sorting is only related to affective polarization among the most politically knowledgeable, affective polarization has increased across all levels of political knowledge. Finally, affective polarization may also increase sorting, further complicating any clear cut causal relationship.

Many Americans associate themselves with their political party in a deep, visceral way. Voter identification with a political party has powerful implications for not just how voters behave, but how there are exposed to and receive information about the world. We describe how this tying of one’s self-concept to a party, which can be analogous to die-hard sports fandom, plays a central role in political cognition. It leads voters identifying with the two parties to perceive the political (and even seemingly apolitical) world in dramatically different ways. We detail the psychological mechanisms by which this party identity produces these distortions and offer examples of the bias that emerges. We conclude by discussing the implications of these phenomena for perpetuating our current hyper-polarized political discourse.

Political constraint and issue consistency are key variables in the study of public opinion, but the existing literature contains many parallel but contradictory accounts of the sources and predictors of ideological constraint. Some posit that constraint is essentially a function of a person’s partisan commitment, others suggest it is rooted in participation in politics, while others see a wide range of correlates summarized as “sophistication.” Still others deny that constraint exists in the mass public altogether. Contrary to these accounts, we argue that issue consistency exists within the American public and is best predicted by political knowledge, which should be thought of as separate from those other predictors. In fact, after accounting for political knowledge, other variables like partisanship, participation, and demographic variables have little independent relationship to ideological constraint. The data show that political knowledge is about as strong a predictor of issue consistency as is one’s self-placed ideology – a widely used proxy for constraint. These results help us understand how citizens think about politics and which groups of people most closely resemble elites in the structure of their opinions. Our findings show that previously hypothesized predictors of constraint – particularly partisanship and participation – are mainly related to ideological constraint through a person’s level of political knowledge.

Using daily polling data collected during the 2016 election, we examine the impact of fundamental conditions, campaign events, media coverage, and other relevant events and announcement on preference dynamics. We observe shifts in voter preferences for president over the course of the campaign and find evidence that these dynamics can be explained by specific circumstances and conditions. Our findings reinforce the potency of fundamental conditions, like presidential approval, but they also demonstrate that political events like national nominating conventions and debates can affect preferences in meaningful and enduring ways. Importantly, our research also suggests that developments commonly perceived to have affected voter preferences in 2016, like FBI Director James Comey’s memo to Congress about Hillary Clinton’s e-mails in October, likely exerted a minimal impact on the election, at least once the impact of other factors are taken into account. In this respect, some of our findings conflict with conventional accounts of campaign dynamics in 2016.