One primary goal for political psychologists is to understand, explain, and eventually predict people’s political beliefs, attitudes, and behaviours. This involves examining how personal and group “identities” influence political opinions and actions. Here, “identity” refers to the way individuals see themselves in relation to groups they are part of or not (e.g., nationality, sex, class). Crucially, individuals are more likely to engage in behaviours consistent with their identities and perceived interests (Blader, 2007; Turner & Reynolds, 2003, p. 201). In other words, identity constitutes a more or less accurate set of beliefs about us and our interests within the social structure.

Yet, identities are not formed in a vacuum; they are shaped by social, material factors, including historical narratives and consensual definitions established by others (Cikara et al., 2022; Spears, 2021; Tajfel & Turner, 1979, p. 41). These dynamics are evident in politics, where parties not only appeal to existing identities but also actively shape or even promote new ones (Brown & Hohman, 2022; Mudde & Kaltwasser, 2017). Therefore, when trying to understand political behaviour, it is important not only to ask people what they think, but to study the broader framework in which their opinions take place.

In this sense, Flores-Robles et al. (2025) highlight the consideration of “committed leftists” as a “distinct and meaningful” group, outside the traditional liberal-conservative spectrum. They do so largely based on how US leftists understand “their own identity” and how “their moral judgments about the status quo distinguish them from their liberal counterparts”. Certainly, such distinction sounds significant, reflecting different ideological frameworks, priorities, and approaches to social and economic issues. Yet, it can be controversial and debatable; the very definitions of liberalism and leftism are.

This paper examines leftism as a political, dynamic phenomenon. First, it analyses its historical roots and the left-right/liberal-conservative spectrum overlap. Then, it contrasts attitudes between leftists and liberals—and, most notably, between leftists—offering a broader taxonomy of their different ideological foundations and attitudes towards key issues, which may inform future comparative research across political systems. Crucially, this paper argues that identities (or ideologies) are not static but dynamic, shaped by—and shaping—social and material contexts (Blader, 2007; Marx, 1859/1999; Turner & Reynolds, 2003). Political attitudes and behaviours emerge from this dialectic. That is, the attitudinal dimension and identity (or ideologies) are mutually constitutive: shared attitudes reinforce group identity, while group identity raises the likelihood of shared attitudes. This framework avoids treating leftism as merely a label or a fixed set of beliefs. Subsequent sections explore implications for political psychology and activism.

The first use of the term “liberal” by a political group was in Spain in the early 19^th century, by those who opposed Napoleon and the subsequent restoration of the monarch’s absolute power. The term then spread to other countries and languages with analogous meaning. The label “leftist”, meanwhile, emerged in the late 18^th century during the French Revolution. This was the origin of the left-right metaphor, being leftists those who opposed absolutism in the French National Assembly. That is, both terms have a common ideological and historical root (Enlightenment principles, ideas of progress and reform, opposition to the ancien regime, etc.). Likewise, both reflected the interests of the then revolutionary class, the bourgeoisie, i.e., individual freedom, limited government, and free market (at least initially). Yet, both groups diverged in their approaches to achieving ideal society, especially over time and in different countries. Even the label liberal now carries contradictory meanings (see Ball et al., 2024).

In contemporary usage, the left-right spectrum reflects a continuum from egalitarian, system-change positions (left) to hierarchical, status-quo-preserving ones (right), at least in the bourgeois democracies (Bobbio, 1996). Dominant left-wing factions may also adopt system-maintenance functions upon seizing power, yet their anti-capitalist character would endure provided they suppress the bourgeois counter-revolution and advance socialist construction—even as minority factions further to the left, adhering to more radical critiques, persist (Lenin, 1920/1974). Thus, despite their bourgeois origins, the left-right metaphor maintains its polar or axiological meaning (Bobbio, 1996; Thorisdottir et al., 2007).

The liberal-conservative spectrum, however, operates differently. Where Marxist influence remained limited (e.g., the US), liberalism largely retained its original progressive character (Caprara & Vecchione, 2018). Conversely, wherever socialist movements gained prominence (e.g., Europe), liberalism acquired a right-wing connotation: after all, it was the ideology of the bourgeoisie—progressive in dismantling the ancien régime, yet still conservative vis-à-vis working-class interests (see Marx & Engels, 1846/1968, pp. 22-23). Indeed, once the bourgeoisie became the dominant class—either replacing or allying with the nobility—liberalism, as its ideology, became somewhat synonymous with conservatism. It is significant how right-wing parties in Europe call themselves “liberal conservatives” or “Christian democrats”. These parties ostensibly champion free market and minimal state intervention (though they may resort to such intervention to protect property relations or safeguard the interest of the dominant class). In turn, they frequently remain traditional in social issues (i.e., they defend the “new” bourgeois status quo). They are sometimes termed or related to “neoliberals”, to distinguish them from the social-liberal tradition (see Smith, 2024).

Thus, in Europe, modern leftism may be seen as analogous to 18^th century liberalism in that both seek to overcome an oppressive status quo and establish a more egalitarian society. Indeed, advocates of socialism—particularly proponents of “scientific socialism”—view themselves as heirs to Enlightenment principles and French revolutionists (Engels, 1880/2003). Socialism, in turn, laid the foundations for European social democrats, which today constitute one of the two dominant political forces, alongside their centre-right counterparts: the liberal conservatives (or, in some countries, “popular parties” or Christian democrats). Admittedly, there are also liberal parties in Europe (economically liberal, thus right-leaning, yet often progressive on civil rights). These parties frequently act as “kingmakers”, enabling either centre-right or centre-left governments by supporting liberal conservatives or social democrats, respectively. Though smaller factions exist on both the right and the left, social democrats and liberal conservatives dominate politics in most European nations and in the EU Parliament. Consequently, in Europe, the left-right divide carries a more polar or axiological weight than the liberal-conservative one.

In the US, meanwhile, liberalism retains a connotation of progress and reform. This may come as a surprise, given that the bourgeois class also rules there, yet, as already noted, one possible explanation is that socialism did not take root in the US. In turn, it would be due to specific material and historical factors. For example, as Flores-Robles et al. (2025) point out, socialism suffered severe persecution there (the “Red Scare”). As the case may be, in the US Congress, there aren’t parties other than Republicans and Democrats. The former is generally considered conservative, or more recently, “right-wing populist”, whereas the latter positions itself somewhat to the left on economic issues and is considered more liberal on civil rights (Arhin et al., 2023; Smith, 2021). Accordingly, the liberal-conservative metaphor is the meaningful one in the US.

In short, the label liberalism became conservative in Europe (post-bourgeois consolidation) but retained progressive connotations in the US (due to socialism’s marginalisation). Yet, certain overlap between the two spectra might be considered.

Following the above, Europe may seem more liberal or leftist than the US. European social democrats seem stronger advocates of welfare states than US Democrats. Even European liberal conservatives seem more in favour of welfare states than US Democrats, and certainly more than Republicans (Gingrich & Häusermann, 2015). In fact, the latter tend to align themselves with the European Conservatives and Reformists Party, i.e., a political bloc further to the right than liberal conservatives. This could also be explained by material, historical factors: the working-class roots of European social democrats, the Christian democrats’ determination to counter the “Red Menace”, and proximity to the USSR, could have made European politics gravitate more towards socialism (Dudziak, 2000; Gilman, 2003, pp. 42-46, 58, 2017; Gregory & Stuart, 2014, p. 290).

On another note, EU governance is often shaped by de facto coalitions of social democrats and liberal conservatives, with liberal and green support (see Raunio, 2022). Such coalitions dominate the European political landscape, giving it a degree of stability vis-à-vis Eurosceptic parties. In fact, European parties could be placed on one Europeanist-Eurosceptic axis, without clear equivalent in the US. Euroscepticism can be found both on the right of liberal conservatives (i.e., among European Conservatives and Reformists, Patriots for Europe, and Europe of Sovereign Nations groups) and on the left of social democrats (i.e., among European United Left-Nordic Green Left groups). In the US, too, there would be secessionist sentiments, most pronounced among Republican voters (Jacobs, 2024). Yet, it would not, in principle, be as singled out, or branded as anti-system, as Eurosceptics are (Brack, 2018).

Notwithstanding the foregoing, we can consider an overlap between both liberal-conservative and left-right spectra (see Eldridge, 2024). That is, American and European political systems would be not so different after all. First, though European social democrats and liberal conservatives may unite against populist or Eurosceptic parties, they ultimately compete for power, mirroring the dynamic between Democrats and Republicans in the US. That is, both social democrats and liberal conservatives, and Democrats and Republicans, represent two sides of the same bourgeois project. The former advocate more market regulation and social justice; the latter, free market and traditional values (at least on paper).

Second, the defence of welfare states is less contested in the EU than in the US. However, this is ceasing to be the case due to material, historical factors such as the fall of the USSR and the weakening of the “Red Menace” (Gilman, 2017). In fact, European welfare states are being dismantled to a large extent and European social democrats are moving to the right, further away from their socialist origins (Navarro, 2013). Consider Tony Blair’s Third Way, or how British Labourites get closer to (neo)liberalism (Navarro, 1999). Occasionally, e.g., in times of economic crisis, socialist-inspired leaders emerge within the European social democrats (e.g., Jeremy Corbyn in the UK) or even within the US Democrats (e.g., Bernie Sanders), though their tenure tends to be short-lived.

Indeed, the far-right seems to be growing in Europe (Aktas, 2024). The European political landscape arguably heads towards two large political coalitions; one of social democrats, liberals, and greens, and perhaps some liberal conservatives (which would amount to US Democrats), and other liberal conservatives, conservatives and reformists, patriots, and sovereigntists (closer to Republicans). Both would defend, to varying degrees, liberal positions (in an economic sense). None would question society’s material foundations (the capitalist mode of production) nor confront the ruling elite. Differences would be confined to civil rights.

So, there would not only be an overlap between the two spectra; there would also be, or would tend to be, an overlap between European social democrats (and other centre-left forces) and US Democrats, on the one hand, and between European liberal conservatives (and other right-wing forces) and US Republicans, on the other. Meanwhile, leftists remain absent from the US Congress and are a dwindling minority in the European Parliament (see Aktas, 2024; Azmanova, 2004). Yet, they still advocate welfare states and the regulation of capitalism to a greater extent than social democrats, and to a much greater extent than US liberals. Therefore, it seems reasonable, in principle, to posit leftism as a distinct and meaningful “anti-capitalist” (or “post-capitalist”) option, in both Europe and the US, even outside the political spectrum. Yet it may be a hasty conclusion.

Political groups, be they parties or social movements, are often defined in relation to other groups, on the basis of what differentiates them. Thus, to define leftists we may compare them with US liberals (and/or with European social democrats). Let us see some differences:

Classifying the existing lefts is a major challenge, given the many variables and nuances in their ideologies, strategies, and historical contexts. Yet, let us consider a working taxonomy, based on the same aspects that we saw to explain differences between leftists and liberals/social democrats.

The foregoing highlights several types of leftist movements and approaches. Each category could be further subdivided or nuanced, though such classifications must account for the dynamic nature of political landscapes. Parties frequently shift their stances on issues, while internal factions or traditions may advocate for divergent, even contradictory, stances. These tensions generate passionate debates that can lead to splits, the formation of new parties, and seemingly irreconcilable standpoints. At other times, ostensibly opposed groups may form tactical alliances in pursuit of shared objectives. Together, these dynamics underscore the complexity of categorising leftist movements.

A parallel challenge would apply to the taxonomy of “rightists”. It may also seem that they form a “distinct and meaningful group” from US conservatives (or from liberal conservatives, Christian democrats, etc.). That is, just as leftists may be conflated with liberals, rightists are often labelled as, or merged with, fascists, neoliberals, anarcho-capitalists, etc., perhaps due to their shared opposition to socialism. Yet, like their leftist counterparts, rightists too exhibit significant ideological and strategic diversity, even as they forge alliances with centrist or moderate factions. While no classification can fully capture this heterogeneity, the proposed framework offers a provisional map to help situate researchers.

Also worthy of mention is the potential limitation of the Eurocentric perspective inherent in the concepts employed. This is, to some extent, unavoidable given the subject matter. On the one hand, the very origins of terms such as left/right and liberal/conservative lie in Europe, emerging during a period when much of the world was under its colonial domination. Like technological advancements and other ideological or cultural productions, their influence was largely unidirectional—though it occasionally provoked resistance, leading to reinterpretations or hybridisations, such as African or Arab socialism (Takriti & Safieddine, 2022).

On the other hand, countries in the so-called Global South continue to employ similar terminology, albeit adapted to local contexts. Even the names of political parties and movements often overlap with their European counterparts. That said, analogous political dynamics exist worldwide, with the economic question—i.e., the production and distribution of wealth—forming the foundational axis of political conflict, even if it is not always the most visible dividing line. Ultimately, one might expect to find, in every context, at least two fundamental political tendencies: one defending the interests of a privileged minority and another opposing it (albeit with intermediate variations and context-dependent compositions). While these tendencies may be labelled differently, they reflect universal structural tensions.

From a social psychological perspective, replicating the study of Flores-Robles et al. overseas could prove illuminating. For example, analogous differences between leftists and social democrats would likely emerge in Europe, though mediated by differing historical and material conditions. Likewise, deepening this line of research—both within and beyond the US—would significantly advance scholarly understanding in the field. For example, the US leftists examined in their study could be categorised as: (1) classical socialist leftists, (2) post-materialist leftists, or (3) liberals dissatisfied with Democrats. Further meaningful subdivisions could include leftists who: (1) instrumentally support Democrats for immediate self-interest seeking (e.g., career advancement), (2) systematically reject Democrats (whether they participate in politics or not), viewing both major parties as components of the same bourgeois project, or (3) paradoxically align with Republicans out of other, immediate self-interest seeking (e.g., right to bear arms). While additional context-dependent subdivisions could be identified based on secondary aspects, leftists across contexts would generally conform to the taxonomy outlined in the “different lefts” section.

Also from a social psychological perspective, we might explore the relationship between dispositional factors, personality traits and/or basic motives, and attitudes towards social issues or political strategies. Various conceptual frameworks have been proposed for this analysis. For instance, Eysenck (1956) introduced a two-dimensional model consisting of a horizontal radicalism-conservatism spectrum (R-axis) and a vertical tender-minded/tough-minded dichotomy (T-axis), with the latter reflecting varying degrees of authoritarianism. However, critics argue this framework problematically conflates left-wing radicalism (typically rooted in egalitarian principles) with right-wing authoritarianism under the “tough-minded” label, thereby obscuring their distinct motivational foundations (Costello et al., 2022; Eldridge, 2024; Stone, 1980).

Eysenck’s model inspired subsequent biaxial tools like the Political Compass, which positions ideologies along left-right (economic) and libertarian-authoritarian (social) axes. However, these instruments inherit Eysenck’s core limitation: they reduce complex, dynamic ideologies to static positions, artificially conflating incompatible forms of extremism (e.g., Stalin’s centralised collectivism with Hitler’s ethnonationalism) within oversimplified categories. The Political Compass has drawn particular criticism for its libertarian bias—reflecting a tendency to narrowly equate authoritarianism with state power while systematically neglecting corporations and other non-state structures of domination (Eldridge, 2024; Mudde, 2019).

Additionally, biaxial models would fail to capture how individuals strategically shift positions across issues (e.g., supporting both economic redistribution and immigration restrictions). This may tempt researchers to add additional axes, as many as there are social issues and ways to deal with them, aiming thus to capture the complexity of human political behaviour and situate respondents (e.g., short- versus long-term foresight, centralisation versus decentralisation, protectionism versus free market, developmentalism versus degrowth, nationalism versus internationalism, communitarianism versus individualism, interventionism versus non-interventionism, clericalism versus anticlericalism, etc.). Although this may be helpful for exploring beliefs, attitudes, etc., of individuals and groups at specific moments, regarding specific issues, it is important not to lose sight of the contextual dependency and the dynamic nature of such beliefs, attitudes, etc. For example, during economic crisis, support for populist, radical, or even authoritarian political options may increase (Funke et al., 2016; Hernández & Kriesi, 2016). In turn, individuals choose among the available options and create new ones (Alesina et al., 2001; Żuk & Toporowski, 2020). Narrow, static models might fail to account for the context-dependent and dynamic nature of human political behaviour.

Admittedly, social psychology has a long-standing tradition of examining how dispositional factors determine political preferences. For instance, leftists/liberals are typically characterised by higher openness to experience, lower conscientiousness, and reduced social dominance orientation, compared to rightists/conservatives (Adorno et al., 1950; Bakker, 2023; Caprara & Vecchione, 2018; Duckitt, 2015; Federico, 2022). Likewise, empirical studies suggest a direct linkage between the Big Five personality traits and ideology, though their predictive power may be weaker than that of social attitudes like authoritarianism (Gerber et al., 2010). Moreover, others suggest that the effect of dispositional factors on ideology may have been overestimated, with no direct influence of the former on the latter, such influence varying across countries and contexts, or ultimately there being no significant physiological differences between leftists/liberals and rightists/conservatives (Bakker et al., 2020, 2021; Fatke, 2017; Panagopoulos & Lehrfeld, 2015).

That is to say, dispositional factors might have probabilistic effects upon individuals’ political preferences, though an individual’s position within the social and economic structure—along with profound changes to that very structure—typically proves more decisive (Brandt, 2013; Vargas-Salfate et al., 2018; Wright, 2015, pp. 124-125 and 153). Indeed, the fact that people sometimes rebel, while at other times they do not, fundamentally resists explanation through stable dispositional factors. The reason activists with similar personality traits (e.g., openness) adopt opposing strategies (e.g., reformism versus revolution) most likely lies in their material and historical context. One specific example: openness generally correlates with preferences for equality, but is linked to left-wing ideologies in Western Europe and right-wing in Eastern Europe, while need for security is associated with right-wing in Western Europe and left-wing in Eastern Europe (Thorisdottir et al., 2007). Material, historical factors beyond dispositional or motivational variables should be considered.

This tension between bottom-up and top-down explanations lies at the heart of political psychology’s explanatory challenge (see e.g., Jost, 2019; Owuamalam et al., 2019; Owuamalam & Spears, 2020; Turner & Reynolds, 2003). As a conciliatory approach, one might propose rejecting both strict structural determinism (top-down) and atomistic individualism (bottom-up), recognising instead that political identification emerges from perceived interests shaped—but not wholly determined—by power asymmetries and other contextual factors. It would retain space for human agency.

Thus, to understand why certain ideologies and political strategies prevail over others, and eventually predict phenomena such as system-challenging collective actions, multidisciplinary approaches appear advisable, prioritising the broader context in which individuals’ political behaviour takes place. For its part, political psychology will always play an essential role; beyond mapping human potential and limitations, it would help us to understand and, ultimately, to predict how individuals might react in given circumstances.

Finally, with regard to activism, the assumption that political preferences are entirely top-down—determined solely by forces beyond individual agency—leaves little room for change. The same applies to purely bottom-up perspectives, which treat social identities as context-independent phenomena or view the system as merely reflecting innate individual differences. Arguably, people align with what they perceive as beneficial, while having these very perceptions shaped within asymmetric power structures. But they remain active agents, whether through action or inaction. In this sense, a well-organised group conducting rigorous scientific analyses, coupled with strategic planning and effective communication, could significantly enhance its capacity to effect societal change.

Yet, groups operate within ever-changing contexts, often facing dilemmas that might challenge their political strategy (i.e., revolutionary or reformist, electioneering or grassroots, etc.). These dilemmas warrant in-depth discussion, and many more dilemmas can arise (as many as there are social issues and ways of dealing with them exist). Some, if not all, may be false or apparent dilemmas. E.g., we are often confronted with discussions about whether the economy should be subject to intervention or not, and yet someone always does it, whether it is the state or business. The dilemma in this case would be who intervenes and for what purpose, or for the benefit of what class.

Electorally, the liberal-leftist (or among leftists) distinction has practical significance: participating in the institutions (e.g., by voting for liberals/social democrats, joining their parties, or even entering coalitions) or remaining outside them (e.g., pressing on the streets to influence rulers). The first option may offer short-term advantages, such as advancing certain policies and gaining governance experience. However, this risks systemic co-optation, which can lead to voter disillusionment, thereby paving the way for rivals. The second option, meanwhile, preserves ideological purity. However, it often struggles to scale demands and risks marginalisation, which can also foster disillusionment and also pave the ground for rivals. The context determines the optimal approach. Those who know history will be better able to choose. Even so, there is no perpetually effective option. The most sensible course for leftists in this case, as Lenin (1920/1974) suggested, is to combine institutional participation with sustained mass mobilisation.

In short, any political group seeking to attain power must ground their efforts in rigorous scientific analysis, develop adaptive strategies and need-based programs, and communicate them effectively, all while preserving the flexibility to navigate changing political landscapes.

Leftists constitute a heterogeneous group, divisible by ideological foundations, socioeconomic stances, and political strategies. This results in diverse political parties and social movements, sometimes complementary to each other—and even to options further to their right, such as liberals or social democrats. At other times, however, differences in beliefs, identities, and/or interests, arising from distinct historical and material experiences, lead to irreconcilable positions. In such cases, internal splits or conflicts may occur, which opposing forces can exploit.

As a take-home message for researchers and activists, it is essential not to separate ideologies from those who produce them, nor from the objective, material, and historical contexts that allow their production. For instance, when analysing—or attempting to influence—beliefs, attitudes, and behaviours towards wealth distribution, one must first consider how wealth is produced. While a complete grasp of reality remains a chimera—given its elusive, dynamic, and ever-changing nature—the very attempt to comprehend it may enhance effective cooperation and conflict resolution strategies.