It is undoubtedly ironic that one of the Founding Fathers of the United States – the birthplace of hyper-partisanship and polarization – had a premonition of the dangers of “unbridled partisanship” in the early days of the American republic. Fast-forward 245 years, as Washington’s warning comes to fruition in the form of partisan acrimony that culminated in the January 6th insurrection at the US Capitol, the symbolic core of American democracy. A YouGov poll conducted the day after the insurgency revealed that 45% of Republicans approved of the storming of the Capitol while 52% of Republicans blamed Joe Biden for the actions of those who attacked the Capitol.Footnote ¹ This was not an isolated incident. Only a few weeks later, members of Congress called for the removal of Representative Marjorie Taylor Greene, a Republican from Georgia, following revelations about past social media posts in which she called for violence against Democratic politicians.Footnote ² In August 2021, the US Department of Homeland Security issued a bulletin warning of a continued threat from domestic violent extremists whose actions are fueled by false narratives about fraud in the 2020 US presidential election.Footnote ³ Critics might argue that political violence is not a completely novel phenomenon in US history. After all, violent fringes on both sides of the ideological aisle have been in existence since the late 1960s, committing violence in support of social causes, such as the far-left Weather Underground Organization as well as the anti-abortion group Operation Rescue. However, the political violence in the twenty-first century is no longer exclusively driven by a few ideologically extreme fringe groups. Instead, the January 6th insurrection was driven by a “broader mass movement with violence at its core” (Chicago Project on Security and Threats 2021, p. 4) that, in contrast to past extremists’ groups, includes older, employed Americans without an affiliation to a militia such as the Proud Boys or the Aryan Nation but with a strong party affiliation.Footnote ⁴ Indeed, a recent nationally representative survey reveals that among Americans who identify as Democrat or Republican, one in three now believe that violence could be justified to advance their parties’ political goals.Footnote ⁵ These patterns constitute a textbook example of “unbridled partisanship” and its damaging effect on Americans’ commitment to democratic norms and values including the peaceful transition of power, the recognition and protection of fair and legitimate elections regardless of their outcome, as well as civil and respectful discourse between leaders and members of opposing parties.

Yet the United States is not the only country that has been struggling with the dangerous consequences of uncritical party loyalties and violent rhetoric: Many of Europe’s mainstream political parties are facing off with populist challengers who frequently espouse anti-democratic and illiberal values. Italy, for example, is equally familiar with claims of election fraud by a losing party: In 2006, Forza Italia, led by Berlusconi, did not accept its defeat and called the election outcome illegitimate, which marked the beginning of hostile and confrontational relations between the parties in the legislature (Donovan Reference Donovan, Donovan and Onofri2008). This emerging conflict was further exacerbated when Berlusconi returned to office in 2008, creating a political climate that normalized the demonization of and aggression toward opposing parties (Bosco and Verney Reference Bosch and Durán2020). Indeed, the partisan vitriol became so intense that, at the time, President of the Republic Giorgio Napolitano described Italy as “torn by hyper-partisanship, a daily guerrilla, a reciprocal delegitimization.”Footnote ⁶ The Italian version of hyper-partisanship resembles its American counterpart in the sense that it, too, is driven by polarizing party elites who benefit from the partisan rancor, such as Berlusconi and, in contemporary Italy, Northern League leader Matteo Salvini whose “innovative use of the social media, dialectic ability and aggressive language polarised and divided the electorate as only Berlusconi had done in the past” (Bosco and Verney Reference Bosch and Durán2020, p. 275). Concurrently, anti-racist groups in Italy report increasing violence against migrants, including 12 shootings, 2 murders, and 33 physical assaults recorded in just the two months after the leader of the far-right Northern League, Matteo Salvini, took office in 2018.Footnote ⁷ More such incidences are predicted in the aftermath of the electoral victory of Italy’s far-right Brothers of Italy in the 2022 general election – a party that originated in the neofascist Italian Social Movement and that is known for its aggressive rhetoric against migrants, the LGBTQ community, and reproductive rights.Footnote ⁸

Even in Sweden – otherwise known for its progressive policies – a nationalist, anti-immigrant party, the Sweden Democrats, is steadily gaining support. The party was long seen as marginal; but in 2022, it is Sweden’s third-largest party, holding 60 seats in the 349-seat parliament (Ahlander and Johnson (Reference Ahlander and Johnson2021). As their electoral appeal is growing, so are levels of animosity toward the Sweden Democrats (Reiljan and Ryan Reference Reiljan and Ryan2021) with 43% of Swedish citizens reporting that they would never vote for the Sweden Democrats – followed, in second place of Sweden’s most unpopular parties, by the left-wing Feminist Initiative, which only 10% of Swedes would never vote for (Bankert Reference Bankert, Oscarsson and Holmberg2020). Note the large gap between these two parties: almost half of the Swedish electorate appears to be unified in their aversion to the Sweden Democrats. These numbers align with the prediction that successful populist parties can collapse and divide political competition into a struggle between “liberal democracy” as represented by establishment parties in the political center and “populism” as represented by the strongest populist party (Mudde and Kaltwasser Reference Mudde and Rovira Kaltwasser2018). This struggle has also been accompanied by higher levels of partisan acrimony whereby many Swedes share more negative, rather than positive, feelings toward their political parties (Bankert Reference Bankert, Oscarsson and Holmberg2020). Concurrently, researchers have also been documenting “an increasing frequency of threats and hatred voiced against politicians and officials” (Oscarsson et al. Reference Oscarsson, Bergman, Bergström and Hellström2021, p. 5) as was exemplified by the stabbing of a public health official at the hands of a Neo-Nazi supporter at Sweden’s annual democracy festival in July 2022 (Pelling 2022).

The rise of negativity toward one or several political parties is also characteristic of the Netherlands, where Dutch voters report more negative feelings for people from different political parties than for people from nonpolitical groups such as those from different religious, educational, or ethnic backgrounds, a startling trend given the Netherlands’ tradition of a consociational and consensus-oriented democracy. This negativity directed at political out-groups illustrates the emergence of hostility along party lines, especially between those who support and oppose the populist radical right parties (Harteveld Reference Harteveld2021) – similar to Italy and Sweden. While many Dutch citizens fiercely oppose the populist right, its supporters feel a similarly deep disdain for adherents to establishment parties, which leads to a “‘double boost’ of antipathy to the system by [the populist right] being both the object and subject of unique antipathy” (Harteveld Reference Harteveld2021, p. 10). Yet even more generally, some Dutch partisans report more negative feelings and a sense of greater social distance toward opposing parties while also ascribing more negative traits toward their supporters (Heeremans Reference Heeremans2018) – a partisan division that has intensified during the COVID-19 pandemic (Krastev and Leonard Reference Krastev and Leonard2021).

Last, the United Kingdom too has seen a rise in political threats and violence against politicians (Parker, Pickard, and Wright Reference Parker and Wright2021). Most recently, conservative Member of Parliament (MP) Sir David Amess was assassinated in Essex in October 2021. He is the second serving MP to be killed in the past five years, following the murder of Labour MP Jo Cox in 2016. Again, these are not isolated cases. Between 2016 and 2020, the Metropolitan Police recorded 678 crimes against MPs, including 582 reports of malicious communications, 46 cases of harassment, and 9 relating to terrorism (Parker, Pickard, and Wright Reference Parker and Wright2021). Some political pundits consider the hostile rhetoric between party leaders responsible for these violent trends. Indeed, there are many examples of violence in political elites’ rhetoric such as referring to their colleagues across the aisle as “a bunch of scum” and “absolute vile” and even suggesting that a bomb should be planted in their office (The Guardian 2021). This bellicose political discourse has downstream effects on the mass public since partisans mirror the behavior and attitudes of their party elites (Huddy and Yair Reference Huddy and Yair2021). Not coincidentally, British partisans discriminate against members of the opposing party more so than they favor their own (Westwood et al. Reference Westwood, Iyengar, Walgrave, Leonisio, Miller and Strijbis2018). In other words, the disdain for the opposing party and its members exceeds the support for one’s own party. The negativity that permeates the political discourse is also connected to lower levels of satisfaction with democracy. While 47% of Britons in 2017 reported feeling dissatisfied with the way democracy was working in their country, this number increased to 69% in 2019,Footnote ⁹ which constitutes a substantial jump within a short time period.

The United States, the United Kingdom, Italy, Sweden, and the Netherlands – these countries differ dramatically in their political culture, the socio-demographic makeup of their voters, as well as the institutional features of their political systems such as the number of parties, their ideological distinctiveness, and their degree of collaboration within or outside a governing coalition. Yet despite these stark differences, these countries seem to face a similar challenge relating to the increasingly acrimonious way citizens perceive and engage with their political opponents. These antipathies have a negative impact on more than just relationships between political parties; they are also connected to a weakened commitment to democratic norms and values that leads partisans to be more accepting of violence toward opposition party leaders and their supporters as well as more willing to infringe upon their democratic rights and freedoms. To illustrate this point, let us have a cursory look at some of the data that I will introduce and analyze in subsequent chapters: In one of my recent surveys of partisans in the United States, almost half of respondents considered their political opponents a serious threat to the country; among those, 25% believe that some parties and candidates should be barred because of their beliefs and ideologies, and 15% agree that violence might sometimes be necessary to fight against parties and candidates that are bad for the country. These indicators of partisan rancor are not just an American phenomenon. Even in Sweden, 31% of partisans consider their opponent a threat to the country, 41% of those would prefer banning certain parties, and 19% agree that violence against these parties might be necessary. The number of partisans who are willing to at least consider violence is also substantial in the United Kingdom (32%), the Netherlands (35%), and Italy (28%).Footnote ¹⁰ Clearly, partisanship is not just a powerful and complex concept in the United States and its infamous two-party system, but also in many European multi-party systems, which warrants a close and comprehensive examination of its origins, expressions, and impact on political behavior – both from a theoretical as well as empirical perspective. This is, at its core, the purpose of this book.

Despite the ubiquity and necessity of political parties in mass democracies, there is a lively scholarly debate regarding the nature and consequences of partisanship: In its classical definition, partisanship reflects a voter’s well-defined political preferences as well as a reasoned and informed understanding of the parties’ positions and their leadership’s performance. I refer to partisanship grounded in this type of responsive and informed deliberation as instrumental. The instrumental model of partisanship closely builds on the idea that people can approximate the ideal of a rational decision maker. This Rational Choice paradigm has shaped political science and its adjacent fields for a long time. From this perspective, strong policy preferences and ideological convictions precede and shape our party affiliation. For example, an American voter might strongly oppose abortion and therefore decide to support the Republican Party. Thus, the causal arrow points from policy preference to partisanship. And indeed, there is some evidence supporting this instrumental model, showing that partisanship is grounded in partisans’ assessment of their leaders and party platforms (e.g., Dalton and Weldon Reference Dalton and Wattenberg2007; Garzia Reference Garzia2013). At the same time, however, researchers have found mixed results for voters’ ability to recognize and adjust to ideological changes parties’ political platforms. While Adams and colleagues (Reference Adams, Ezrow and Somer-Topcu2011) find that the public remains unaware of changes in a party’s policy positions, Fernandez-Vazquez (Reference Fernandez-Vazquez2014) reports a slight change in voters’ perceptions that, nevertheless, falls far short of the magnitude of actual change. These findings constitute a challenge to the instrumental model of partisanship: If shifts in parties’ platforms are not registered by voters, then how can they influence voters’ party affiliation?

In response to the limited evidence in support of instrumental partisanship, an alternative expressive approach to partisanship has developed and gained credence in the United States. This model considers partisanship a social identity rather than a reflection of political preferences. This internalized identity minimizes partisans’ responsiveness to and acknowledgment of negative information about their political party, including poor performance, weak leadership, and changing party platforms. Indeed, when partisanship operates as a partisan identity, it motivates partisans to defend their party even in the face of such negative information – which results in a relatively stable political identity (Green et al. Reference Green, Palmquist and Schickler2002) in spite of leadership and policy changes over time. This expressive approach to partisanship is grounded in Social Identity Theory (Green et al Reference Green, Palmquist and Schickler2002; Huddy Reference Huddy2001; Huddy et al.; Reference Huddy, Mason and Aarøe2015 Tajfel and Turner Reference Tajfel, Turner, Jost and Sidanius2004) – a socio-psychological theory that will serve as the main theoretical lens through which I will examine partisanship in this book.

While the predictions derived from the expressive partisanship model appear rather at odds with normative expectations of democratic decision-making, it is important to understand and acknowledge what the nature partisanship is rather than what it should be. After all, partisanship is a powerful influence on people’s political behavior, including but not limited to their voting decisions. Thus, comprehending the nature and origins of our party attachments is a crucial step in understanding how people engage with their political system, even if that means abandoning high ideals of democratic citizenship (see, for example, Achen and Bartels Reference Achen and Bartels2017). As the famous political scientist Schattschneider astutely put it: “We become cynical about democracy because the public does not act the way the simplistic definition of democracy says that it should act, or we try to whip the public into doing things it does not want to do, is unable to do, and has too much sense to do. The crisis here is not a crisis in democracy but a crisis in theory” (Schattschneider Reference Schattschneider1960:127). The expressive model of partisanship offers a possible answer to that crisis in theory; it does not just encompass a rich theoretical framework to derive predictions about actual political behavior, it also provides a blueprint for identifying the causes of partisanship’s negative impacts, such as the dehumanization of political opponents (e.g., Cassese Reference Cassese2021; Martherus et al. 2019), as well as possible interventions that can counteract them. Only after realistically assessing how partisanship operates can we find solutions for its blind spots.

Cynics might argue that political parties themselves are the problem. Indeed, demands for more direct democracy are common (US News & World Report 2016). While efforts to re-think and reinvent democracy are important and valuable, it is not my intention to convince the reader of the necessity and utility of political parties in democratic societies. This book builds on the assumption that modern mass democracies require political parties. While representative democracy has its flaws, there is no shortage of examples of direct democracy gone wrong: From opposition to fluoride in drinking water in the 1950s and 1960s to conspiracy theories about vaccinations against measles and COVID-19; citizens will inevitably fall for other motivational and cognitive biases – with or without political parties.

Given these considerations, this book serves a crucial purpose: It provides a comprehensive overview and extension of contemporary research on partisanship, including not just a review of existing scholarship but also extensive analyses of recently collected data on partisanship and its consequences in the United States, the United Kingdom, Sweden, Italy, and the Netherlands. However, in contrast to prior work, I examine two different types of partisanship: positive partisanship – that is, strong identification with and attachment to a political party – and negative partisanship – that is, strong internalized hostility toward a political party and its supporters. With this distinction, I arrive at a more nuanced assessment of partisanship: Across multiple countries and their political systems, I find that positive partisanship encourages a range of desirable political behaviors such as turnout and even other forms of effortful or costly political participation such as donating to or volunteering for a political campaign. At the same time, most of the problematic attitudes and behaviors that we associate with democratic erosion such as the vilification and demonization of political opponents are more strongly, if not exclusively, related to negative partisanship. Crucially, I demonstrate that these types of partisanship can exist and operate independently of each other, which is important for how we evaluate partisanship and its (anti-)democratic influences.

More generally, I would like the book to function as a field guide for scholars who work in disciplines that are inevitably affected by partisanship’s growing reach, including political science, psychology, anthropology, sociology, and economics. At the same time, I aim to make this book accessible to citizens outside of academia who try to make sense of the partisan rancor and political violence that might have befallen their own country and community. From this perspective, this book might also be relevant for local civic organizers and activists who wish to understand the origins of entrenched partisan divisions in their own communities. While the book relies heavily on scholarly work and statistical analyses, I provide a summary of the results as well as a conclusion at the end of each empirical chapter to make them more accessible to readers from all backgrounds.

The book is organized into two theoretical sections and five empirical parts. The first theoretical section (Chapters 1–2) provides the reader with an understanding of the two main models of partisanship; it compares the socio-psychological conceptualization of partisanship (i.e., expressive partisanship) to its rational choice–based counterpart (i.e., instrumental partisanship). I highlight their different theoretical assumptions about the way people develop political preferences, the empirical evidence in their support (or lack thereof), as well as the normative implications of both approaches for our assessment of democratic decision-making. In the second theoretical section (Chapters 3–4), I introduce the reader to positive and negative partisanship, including a review of prior work on these types of partisanship, their grounding in Social Identity Theory, and a justification for why we should care about their distinctive origins and nature.

After laying the theoretical groundwork, I shift gears and embark on the first empirical section of the book (Chapters 5–6), focusing on the measurement of positive and negative partisanship in survey research. If partisanship – positive and negative – is an identity, then this should be reflected in the way we capture it. The measurement approach I utilize in this book is informed by Social Identity Theory and has been validated by prior scholarship, including my own (see Bankert, Huddy, and Rosema Reference Bankert, Del Ponte and Huddy2017 as well as Bankert Reference Bankert, Oscarsson and Holmberg2020). The second empirical section (Chapter 7) examines the psychological origins of positive partisanship (PPID) and negative partisanship (NPID) whereby I focus on prominent personality traits such as Social Dominance Orientation, Authoritarianism, the Need for Closure, and the Big 5 Personality Traits. Aligned with my expectation, PPID and NPID are related to different sets of personality traits, providing evidence for their independent nature.

The third empirical section (Chapter 8) examines the impact of strong positive and negative partisanship on a range of democratic behaviors, including turnout, vote choice, and other forms of political engagement. For this analysis, I utilize original, individual-level survey data from the United States as well as four European multi-party systems, namely Sweden, the Netherlands, Italy, and the United Kingdom. I focus on these countries since I am somewhat familiar with their political systems due to my prior work but also because this case selection allows me to compare the magnitude and impact of positive and negative partisanship across five drastically different political systems and cultures. The comparative nature of these analyses can also assess the generalizability of the results beyond the US two-party system, which has attracted a large share of attention in prior scholarship. Across all five countries, the evidence shows that negative and positive partisanship differentially impact political behavior. Chapter 8 also includes a brief excursion into a somewhat neglected part of the electorate, namely political independents. I demonstrate that even independent voters can develop negative partisanship – even though they, by definition, lack a positive party attachment. This finding reasserts the notion that negative partisanship can exist independently of any positive party attachments. At the same time, it also sheds light on how even the disdain for a political party can promote political engagement.

In the fourth empirical chapter (Chapter 9), I examine the relationship between partisanship – both positive and negative – and anti-democratic attitudes such as the use of violence against members of the opposing party and the willingness to ban political parties and limit their free speech. The evidence suggests that negative partisanship is the main driver of these disconcerting attitudes and behaviors. While positive partisanship is not completely unrelated to these symptoms of democratic erosion, negative partisanship is much more strongly and more consistently associated with them across all five countries.

The final empirical part of the book (Chapter 10) examines possible ways to foster positive partisanship without intensifying its negative counterpart. For this purpose, I draw from prior experimental research in political psychology that aims to identify interventions to reduce partisan hostility. Utilizing their theoretical insights and experimental designs, I implement three original survey experiments that test the effect of superordinate identities and cross-cutting identities, as well as the impact of party elites’ rhetoric on positive and negative partisanship. Taken together, these experimental results emphasize the power and responsibility of party elites in promoting good partisanship among their supporters. In Chapter 11, I conclude the book with a few reflections on the future of research on partisanship in the United States and beyond as well as a normative assessment of the past and present challenges to democracy posed by negative partisanship.

Overall, I hope to leave the reader with a more informed, more positive, and more nuanced perspective on partisanship; one that enables all readers to critically assess their own party loyalties and one that enables academic readers to identify promising avenues for future research. A healthy and robust democratic system depends, in no small part, on the character of our party affiliations. There is a world in which partisans can strongly identify with their party without vilifying their opponents. The stakes are too high to dismiss such an alternative.