The Rise of Populist Challenger Parties and the Imitation Hypothesis

Populist parties have gained ground in response to citizens’ growing dissatisfaction with mainstream, established political institutions that appear unwilling or unable to respond to their grievances and demands (Bakker, Jolly, and Polk Reference Bakker, Jolly, Polk, Hobolt and Rodon i Casarramona2021; Berman Reference Berman2016, Reference Berman2017; Broz, Frieden, and Weymouth Reference Broz, Frieden and Weymouth2021; Foa et al. Reference Foa, Klassen, Slade and Rand2020). Support for populist parties is in many ways driven by their promise to end the source of rising inequality: globalization (Pastor and Veronesi Reference Pastor and Veronesi2018, Wiesehomeier, Dupont, and Ruth-Lovell Reference Wiesehomeier, Dupont and Ruth-Lovell2024). Working class citizens have been especially likely to respond to populist appeals (Berman Reference Berman2019; Stanley Reference Stanley, Kaltwasser, Taggart, Espejo and Ostiguy2017). The financial crisis of 2008 alone triggered a wave of populist sentiments across established democracies (Eichengreen Reference Eichengreen2018; Funke, Schularick, and Trebesch Reference Funke, Schularick and Trebesch2016; Rodrik Reference Rodrik2012; Schäfer Reference Schäfer2013).

Populist parties frame political discourse around a stark division between the “corrupt elites” and the “ordinary people” (Mudde Reference Mudde2007; Taggart Reference Taggart2000). By doing so, they portray the political establishment as an elite group that prioritized their own economic and political interests, often at the expense of the wider population. This antielite narrative has resonated deeply with voters who feel abandoned or disenfranchised by the traditional parties that they once trusted to protect their interests. Populists promise to reverse this dynamic, presenting themselves as the true defenders of the people against the entrenched elites, both within the country and in international institutions.

Populist parties have also positioned themselves as more responsive to the issues that mainstream parties had neglected or inadequately addressed. For example, concerns about immigration, globalization, and economic insecurity were frequently dismissed or downplayed by the traditional parties, especially in the face of pressures to maintain proglobalization stances. Mainstream parties often respond to such concerns with technocratic solutions or frame issues in ways that do not resonate with many citizens (De Vries and Hobolt Reference De Vries and Hobolt2020). In contrast, populist parties politicize these concerns directly, addressing them with a sense of urgency and in ways that align more closely with voters’ preferences. On such topics as immigration, populists frequently capitalize on anxieties about national identity, economic competition, and cultural change, offering simple (and often extreme) solutions that draw stark lines between insiders and outsiders (Hobolt and Tilley Reference Hobolt and Tilley2014).

Populists also readily tap into the antiglobalization sentiment, appealing to voters who see globalization as a threat to their economic security and national sovereignty. This gives populists a significant advantage over mainstream parties, which often hesitate to take strong stances against international economic integration. By foregrounding antiglobalization and nationalist rhetoric, populist parties effectively build a political identity that contrasts starkly with the establishment’s perceived complicity in the negative effects of globalization, such as job losses, wage stagnation, and economic inequality (Mudde and Rovira Kaltwasser Reference Mudde and Kaltwasser2018; Norris and Inglehart Reference Norris and Inglehart2019). Politicizing globalization and immigration as causes of citizens’ struggles has allowed populist parties to build a broad base of support, while mainstream parties have struggled to adapt their platforms in ways that effectively address these growing anxieties.

There are noteworthy differences between leftist and rightist populist parties. Both types of populists are antiestablishment parties that claim to be championing the interests of the people against elites. However, leftist populists tend to focus more narrowly on economic issues than the nationalist and xenophobic rhetoric that characterizes right-wing populism (Rydgren Reference Rydgren2014). For example, while parties like Syriza in Greece have campaigned on antiausterity platforms and railed against international financial institutions, they have not embraced the anti-immigration rhetoric that has been central to right-wing populist movements (Kitschelt Reference Kitschelt1996; Mudde and Rovira Kaltwasser Reference Mudde and Kaltwasser2018). Like other populist parties that succeeded in entering government, Syriza found it impossible to fulfill many of its radical promises; having campaigned on a platform of rejecting austerity, it was forced to accept an austere bailout package from the European Union (Ruiz-Rufino Reference Ruiz-Rufino2025; Stavrakakis and Katsambekis Reference Stavrakakis and Katsambekis2014). In contrast, right-wing populist parties combine economic grievances with cultural resentment (Mutz Reference Mutz2018). This offers a more emotionally resonant narrative to voters who fear the erosion of traditional values due to immigration and globalization (Kriesi et al. Reference Kriesi, Grande, Lachat, Dolezal, Bornschier and Frey2008; Mudde Reference Mudde2007). Right-wing populist parties – such as the National Rally (formerly National Front) in France or the Alternative for Germany (AfD) – have capitalized on voters’ frustrations with globalization by adopting exclusionary, nationalist rhetoric.

Mainstream parties have had to consider how best to respond to the growing support for populist parties (Rooduijn Reference Rooduijn2014), and they have adopted various strategies, including dismissive, adversarial, and accommodating stances (Meguid Reference Meguid2005, Reference Meguid2008). The imitation hypothesis posits that the most common response by mainstream parties to the rise of populist parties has been one of imitation.Footnote ³ Simply put, leaders of mainstream parties see the success of populist parties and decide to use similar rhetoric and positions in response to this electoral threat. De Vries and Hobolt (Reference De Vries and Hobolt2020) argue that mainstream parties have adjusted to the political climate created by populist entrepreneurs by tapping into antielite sentiment and populists’ demands for national sovereignty and protectionism. Akkerman, Lange, and Rooduijn (Reference Akkerman, de Lange and Rooduijn2016) demonstrate that the rise of populist radical-right parties pushes mainstream parties to engage with populist themes such as nationalism, anti-immigration sentiments, and skepticism toward globalization. This strategic adaptation is evident across a range of established democracies, where mainstream parties, particularly those on the center-right, have shifted their policy positions and rhetorical strategies to appeal to voters drawn to populist alternatives (Meguid Reference Meguid2005). Van Spanje and Van der Brug (Reference Van Spanje and Van Der Brug2009) further explain that mainstream parties adopt populist stances to neutralize populist parties’ success, especially by co-opting their messages on issues like immigration and national identity (see also Abou-Chadi and Krause Reference Abou-Chadi and Krause2020; Hobolt and Tilley Reference Hobolt and Tilley2014). By framing national identity in more exclusive terms and positioning themselves as defenders of traditional values against the perceived threats of globalization, center-right parties have sought to retain voters who might otherwise be drawn to more extreme populist alternatives (Canovan Reference Canovan1999; Mudde and Rovira Kaltwasser Reference Mudde and Kaltwasser2013).

There are many examples that fit the imitation hypothesis. For instance, in France, the mainstream conservative Republicans adopted tougher stances on immigration to counter the rise of the populist National Rally, emphasizing French identity and national sovereignty. Similarly, in the Netherlands, the mainstream conservative People’s Party for Freedom and Democracy moved toward more restrictive immigration policies in response to the populist Party for Freedom. In both cases, mainstream right-wing parties used populist rhetoric to retain electoral support without fully embracing the extreme economic and nationalist positions of their populist rivals.

Populism as a Mainstream Center-Right Party Response

While mainstream parties may indeed imitate the rhetoric of successful populist parties, this does not capture the full story about how globalization affects center-right parties’ electoral strategies. The kernel of the problem lies in the dilemma faced by center-right parties that we described earlier. Center-right parties respond to citizens’ rising expectations of their governments by moderating their stances on socioeconomic policies. However, they cannot fully embrace the policies that would make a discernible difference in terms of reducing economic risks without alienating their core supporters, who favor free markets and deregulation. Instead, these parties have chosen to address voter concerns by emphasizing cultural issues – such as stricter immigration controls, law and order, and national identity – while maintaining their economically liberal stances. By doing so, they respond to the socioeconomic anxieties of globalization while making only marginal adjustments to their traditional commitments to free-market principles (Häusermann, Picot, and Geering Reference Häusermann, Picot and Geering2013).

This approach allows center-right parties to compete in an increasingly uncertain political landscape. Rather than shifting dramatically leftward on economic issues, they offer selective economic adjustments – such as tax incentives or limited welfare programs – while pivoting to cultural populism to address voters’ concerns. Hays (Reference Hays2009) argues that while globalization has heightened citizens’ demands for social protections, center-right parties have navigated these pressures by offering targeted benefits and emphasizing national sovereignty and cultural conservatism. This strategy, which combines piecemeal measures and avoidance, has enabled them to retain electoral support, particularly among the middle class, which seeks security from globalization’s economic and cultural disruptions without fully embracing left-wing policies. Although this strategy avoids real remedies for the economic risks to which citizens are exposed, shifting the attention toward cultural and identity-based appeals is to an extent responding to voters’ real concerns too. Issues such as immigration, national sovereignty, and cultural liberalization have become central concerns for voters affected by the socioeconomic changes brought about by globalization (De Vries Reference De Vries2018; Polk et al. Reference Polk, Rovny, Bakker, Edwards, Hooghe and Jolly2017).

Our argument is not incompatible with the imitation hypothesis. Center-right parties may have learned to use the populist toolbox by observing populist parties in national and foreign contexts.Footnote ⁴ However, our argument that mainstream parties’ use of populist rhetoric is a direct response to the globalization dilemma does provide an alternative explanation that is independent of the existence of populist opposition parties at the national level at any particular time. The United States provides an obvious example of a conservative party that has become consumed by populist rhetoric in the absence of a significant populist party. The US electoral system effectively prevents any third party from emerging even if there was underlying social support for one. Since the mid 2010s the Republican Party under Donald Trump exemplified this dynamic. Trump’s three presidential campaigns, in 2016, 2020, and 2024, heavily emphasized themes of national sovereignty, protectionism, and anti-immigration sentiment, tapping into the anxieties of voters who felt economically and culturally marginalized by globalization. While the Republican Party previously focused more clearly on economic conservatism, the party has pivoted toward identity politics, promising to “Make America Great Again” by restoring traditional values and rolling back the influence of globalism. This shift toward cultural populism allowed the Republican Party to maintain its core economic principles while capturing the support of voters who have become disillusioned by both economic and cultural globalization (Brubaker Reference Brubaker2017; Pirro and Van Kessel Reference Pirro and Van Kessel2017; Vachudova Reference Vachudova2020).

Center-right parties have historically used religious and national issues to sustain broad coalitions of support (Riker Reference Riker1986; Shepsle and Bonchek Reference Shepsle and Bonchek1997). After World War II, the expansion of suffrage exposed these parties to a wider array of voters’ concerns, many of which focused on issues like immigration, national identity, and the perceived erosion of traditional values. Many center-right parties had to adapt to broaden their appeal beyond narrow sections of economic elites. This flexibility has given them an advantage in adapting to changing demands, particularly in response to the negative cultural consequences of globalization. While center-right parties may struggle to offer meaningful economic solutions to low- and middle-income voters who are most affected by globalization, they have learned that emphasizing cultural or value-based issues can allow them to attract voters increasingly concerned about these societal changes (Tavits and Potter Reference Tavits and Potter2015).

By contrast, left-wing parties have been notably less likely to embrace full-fledged populist rhetoric in response to globalization. The question here is whether center-left parties respond to globalization by adopting populist rhetoric and policies, not whether they adopt less populist rhetoric and policies than center-right parties. We argue that center-left parties generally do not respond to globalization by adopting populist rhetoric and policies. One key reason for this is that in response to citizens’ rising expectations of their governments, leftist parties have mainly doubled down on a class-based dimension, pledging to implement policies that protect and improve the lives of the working class, the poor, and those who feel disenfranchised by the global economic system (Hobolt and Tilley Reference Hobolt and Tilley2014; Roberts Reference Roberts2019). These policies, often centered around welfare programs, labor protections, and economic redistribution, resonate with the economic concerns of voters who feel left behind by globalization. As a result, left-wing parties are better positioned to address these grievances without needing to dramatically alter their ideological frameworks. Moreover, leftist parties’ progressive social values have made them less likely to fully embrace populist rhetoric in response to globalization. The problem for leftist parties is not that they do not have appealing policies to reduce the economic risks associated with globalization. Rather, as demonstrated in Chapter 4, the problem is that globalization often constrains them from implementing those policies when they are in government. However, populist rhetoric appears less successful at avoiding retrospective sanctioning.

In sum, we argue that globalization has not only pressured center-right parties to shift to the center of the socioeconomic left–right spectrum but also to adopt populist rhetoric and policy promises in an effort to address the dilemma caused by this ideological adjustment. Center-right parties’ use of populist rhetoric allows them to make relatively modest adjustments to their economically liberal positions, while at the same time appealing to a sufficiently large electoral base to sustain themselves through elections.

Dependent Variable: Mainstream Parties’ Use of Populist Rhetoric

We examine data on the levels of populist rhetoric in the electoral appeals of mainstream political parties across thirty countries between 1970 and 2019.Footnote ⁵ Mainstream parties are parties that are classified as socialist or left, social democratic, liberal, Christian democratic, or conservative using the Manifesto Project’s classification of parties into families (Lehmann et al. Reference Lehmann, Franzmann, Al-Gaddooa, Burst, Ivanusch and Regel2024). We exclude parties that are classified as ecological, nationalist, agrarian, ethnic, or otherwise special issue parties. We also exclude populist parties such as the AfD in Germany or UK Independence Party in the United Kingdom. Populist parties do enter our analysis, but as an explanatory variable, when we control for the electoral strength of those parties to test the imitation hypothesis. The unit of analysis is the political party–election year.

To measure Political Party Populism, we use the populist index by V-Party (Lindberg et al. Reference Lindberg, Düpont, Higashijima, Kavasoglu, Marquardt and Bernhard2022), which is an expert-coded dataset on political parties worldwide and part of the V-Dem Project (Coppedge et al. Reference Coppedge, Gerring, Glynn, Knutsen, Lindberg and Pemstein2020; Lindberg et al. Reference Lindberg, Düpont, Higashijima, Kavasoglu, Marquardt and Bernhard2022). The index captures the extent to which parties rely on populist rhetoric with a focus on the extent to which parties glorify ordinary people and identify themselves as part of them (people-centrism) and the salience of antielite rhetoric. This approach equates populist rhetoric with support for antielitism, people centrism, and a moralized Manichean worldview. Populists tend to depict the elite as self-serving, unresponsive and corrupt, while the people tend to be glorified as morally superior (Mudde and Rovira Kaltwasser Reference Mudde and Kaltwasser2018).

Figure 8.1 shows that there is significant variation in the use of populist rhetoric by mainstream parties across different liberal democracies, underscoring how this strategy is more prevalent in some countries than others. The sample includes only mainstream parties and excludes extremist or fringe parties. In some countries, such as Belgium, Luxembourg, and Iceland, mainstream political parties have used populist rhetoric sparingly. These countries tend to have stable political environments and high levels of trust in government institutions, allowing mainstream parties to maintain relatively inclusive, technocratic, and consensus-driven approaches.

Figure 8.1

Populist rhetoric of mainstream political parties, 1970–2019

Figure 8.1 Long description

The 30 countries plotted are United Kingdom, Switzerland, Sweden, Spain, Slovenia, Slovakia, Portugal, Poland, Norway, New Zealand, Netherlands, Luxembourg, Lithuania, Japan, Italy, Israel, Ireland, Iceland, Hungary, Greece, Germany, France, Finland, Estonia, Denmark, Czechia, Canada, Belgium, Austria, and Australia.

Note: The figure presents a violin plot of the average populism score of mainstream parties by country where the width of the shape reflects the data density, the dot inside indicates the median, and the box elements show the interquartile range. Data are from V-Party.

In contrast, in countries like the United Kingdom, Poland, and Australia, many mainstream parties have high levels of populist rhetoric in recent years. In the United Kingdom, for example, the Conservative Party’s use of populist themes became especially pronounced during and after the Brexit referendum. The party adopted strong antielitist and nationalist rhetoric, framing the European Union as an oppressive foreign power and positioning Brexit as a way to “take back control.” This populist messaging resonated with voters who felt left behind by globalization and distant from political elites in Brussels. The Conservatives emphasized national sovereignty and British exceptionalism, using populist rhetoric to win over voters concerned with immigration, national identity, and economic independence.

Similarly, in Poland, the Law and Justice Party (PiS) effectively leveraged populist rhetoric to consolidate power during its years in government. While in office from 2015 to 2023, PiS consistently framed the political elite, judiciary, and media as detached from ordinary Poles, portraying itself as the defender of traditional Polish values and national sovereignty, especially in opposition to perceived interference from the European Union. The party embraced a nationalist and socially conservative platform, opposing liberal immigration policies and resisting progressive cultural changes. This turn toward populist messaging enabled PiS to maintain mainstream appeal while mobilizing voters anxious about the social and economic consequences of globalization, including job insecurity and cultural displacement.

In Australia, the Liberal Party increasingly adopted populist rhetoric, particularly around issues of immigration and national security. In response to growing concerns over globalization’s effects on the Australian economy and cultural identity, the party adopted tough stances on border protection and immigration control, often framing these issues in populist, nationalist terms. The Liberal Party’s rhetoric around “stopping the boats” and tightening immigration policies resonated with voters who were anxious about the economic and social impacts of globalization.

These examples suggest that populist rhetoric is not confined to fringe movements but is increasingly being incorporated into the platforms of mainstream parties as a strategic response to the pressures and uncertainties posed by globalization. Figure 8.2 further indicates that the trend of populism among political parties is increasing. Whereas mainstream parties in Western liberal democracies used populist rhetoric only sparingly in the 1970s (with an average value of 0.2), the use of populist rhetoric increased to an average of 0.25 in the 1980s and 2000s and then increased more significantly to an average of over 0.3 in 2019.

Figure 8.2

Average mainstream party populism, 1970–2020

Note: The figure plots of the average populism score of mainstream parties across countries over time. Data are from V-Party.

The trend of increasing populism among political parties, as indicated by Figure 8.2, is driven by a combination of long-term structural changes and more recent sociopolitical dynamics that mirror the increasing but varying constraints of globalization. In the early years of the 1970s, mainstream parties in many Western liberal democracies were operating at the tail end of the postwar consensus associated with sustained economic growth. The largest parties generally took centrist positions, and the use of populist rhetoric during this period was relatively rare, as populism was largely associated with fringe movements that capitalized on dissatisfaction with the political establishment. However, several key factors began to shift the political landscape, leading to a gradual rise in the use of populist rhetoric by mainstream parties. First, the economic stagnation of the 1970s and the neoliberal turn of the 1980s – marked by deregulation, privatization, and the weakening of the welfare state – created growing inequality and economic insecurity, particularly among lower- and middle-income voters. This fueled a sense of alienation from the political establishment, which populism could effectively tap into by blaming elites for failing to address these economic grievances. The rise of globalization in the 1990s further intensified this trend, as many citizens felt economically marginalized by the growing integration of global markets, job displacement, and increased competition from foreign labor.

By the 2000s, the populist narrative had found fertile ground in the landscape of increasing concerns over immigration, multiculturalism, and national sovereignty. Mainstream parties, especially on the center-right, began to adopt populist rhetoric to appeal to voters who were anxious about these developments. The 2008 global financial crisis exacerbated these anxieties, leading to widespread disillusionment with the political establishment’s ability to manage the economy and provide security. As a result, the use of populist language surged, with parties across the political spectrum, including center-left parties, increasingly incorporating populist themes such as antielitism, nationalism, and skepticism of international institutions into their platforms.

The marked increase in populist rhetoric by 2019 reflects the culmination of these long-standing trends. In addition to economic and cultural concerns, the growing polarization of political discourse and the rise of social media have contributed to the amplification of populist messaging. Populist rhetoric, which often simplifies complex issues into “us versus them” narratives, is particularly effective in the fast-paced, emotionally charged environment of digital media. Mainstream parties, feeling the pressure of populist challengers and the shifting demands of their electorates, have increasingly resorted to populist rhetoric to remain electorally competitive in a political climate shaped by economic uncertainty, cultural backlash, and distrust of traditional institutions.

Principal Explanatory Variables

As in the previous chapters, the data include cases where parties and governments were exposed to very different levels of globalization, which is our key explanatory variable. As in previous (KOF) chapters, we use the authoritative Konjunkturforschungsstelle Economic Globalization Index, which is an annual weighted aggregation of information on de facto and de jure trade and financial globalization:

• Globalization is the extent to which a country is integrated into the international economy, including information on trade in goods and services, trade regulations, tariffs and agreements, foreign direct investment, investment restrictions, and capital account openness. Data are from Dreher (Reference Dreher2006).

Control Variables

To address omitted variable bias, we include several control variables at the levels of countries, election years, and party programs that have been used in previous research. At the level of election years, we control for:

• Populist Party Vote Share measures the absolute vote share of populist parties in the country (excluding the vote share of the party under consideration if that party is a populist party). Data are from V-Party. Crucially, this variable allows us to test the imitation hypothesis, as well as to test our main alternative globalization hypothesis while controlling for the effects of populist party vote share.

• Organizational Strength measures how strongly a political party is rooted in society. Data are from V-Party.

• Intraparty Concentration captures the extent to which power rests in the hand of one leader or a small leadership elite. Data are from V-Party.

• Left–Right Position measures partisan ideology on the left–right axis from the Comparative Manifesto Project. We use the so-called Right–Left Scale scores, which are also derived from parties’ election manifestos or platforms. Data are from Volkens et al. (Reference Volkens, Krause, Lehmann, Matthieß, Merz, Tegel and Wessels2019). By modeling an interaction between the variables Globalization and Left–Right Position, we can test our main theoretical expectation that it is parties of the center-right that increase their use of populist rhetoric in response to globalization.

• Distinct Party Platform measures the ideological convergence and the existence of a space for contenders to exploit the perceived crisis of representation. Data are from V-Party.

• Corruption captures public sector corruption, or the extent to which public sector employees engage in corrupt activities. Data are from V-Party.

• Economic Growth measures the average growth rate of the country over the lifetime of the government. Data are from the World Bank Development Indicators, compiled by the Princeton Niehaus Center for Globalization and Governance World Economics and Politics Dataverse.

• Per Capita Gross Domestic Product measures the level of economic development. Data are from V-Party.

• Incumbency captures whether the party holds executive office or not at the time of their use of populist rhetoric. Data are from country specialists in the Comparative Pledges Project and supplemented with data from the European Journal of Political Research Data Yearbooks.

• Government Experience takes the value 1 if the political party has had any experience in executive government and 0 otherwise. Data are from V-Party.

Descriptive statistics for all variables are presented in the online Supplementary Material. We standardized all continuous explanatory variables to a mean of 0 and a standard deviation of 1.