Research

Publications

Green but Cautious. How Preferences on European Integration shape Public Opinion on the European Green Deal (with Tarik Abou-Chadi, Jannik Jansen and Nils Redeker)
Journal of European Public Policy (2025)
Paper

The ‘European Green Deal’ was a central issue in the run-up to the 2024 European Parliament elections. Little is known though about voters’ preferences on policy bundles that combine climate mitigation measures with fiscal integration. We argue that EU-level climate policies make voters engage in multidimensional cost–benefit calculations. Voters not only weigh-up the costs of climate policies against their anticipated benefits. They also take the additional costs of deepened European integration into account, comparing them to the benefits of coordinated, European policymaking. We test this argument with a conjoint experiment in Germany, France, and Poland asking voters to evaluate a shared green investment package – a cornerstone of the Green Deal. We find that voters are not opposed to multidimensional climate policies per se. Across Europe, investments in disadvantaged regions, and the (re-)training of workers increase the popularity of green policies. Policies that contain EU-level redistribution are regarded skeptically though. Additional analyses suggest that emphasising the co-benefits of fiscal integration – e.g., its ability to reduce economic dependencies and strengthen international competitiveness – might increase support. These findings demonstrate that the EU is fighting an uphill battle with its Green Deal agenda and have important implications for the design and communication of European green policies.

Kollberg, M., Jansen, J., Abou-Chadi, T. & Redeker, N. (2025). Green but cautious. How preferences on European integration shape public opinion on the European Green Deal. Journal of European Public Policy. https://doi.org/10.1080/13501763.2025.2495677

Communicating a Common Front: Mainstream Party Rhetoric and Affective Polarisation Towards the Radical Right (with Ivo Bantel)
West European Politics (2025)
Paper

Does mainstream party rhetoric explain affective polarisation towards the radical right? Extant work documents a pronounced affective divide between mainstream and radical right voters. Yet, the origins of this divide remain largely unknown. This article investigates negative rhetoric by mainstream parties as a predictor of affective polarisation towards the radical right. It argues that signals of a ‘common front’ – coordinated negative rhetoric against the radical right by all mainstream parties – drive voters’ affective evaluations. The article combines an analysis of elite discourse and public opinion data from Germany, with a novel measure of targeted negative elite rhetoric, as well as causal evidence from an experiment. The analysis identifies a correlation between negative rhetoric from all mainstream parties and affective polarisation towards the radical right. Experimental tests of the previously identified rhetoric yield further evidence that cross-party messages contribute to affective polarisation. These findings underscore the importance of coordinated mainstream party action in shaping public responses to radical right challengers.

Kollberg, M., & Bantel, I. (2025). Communicating a common front: Mainstream party rhetoric and affective polarisation towards the radical right. West European Politics. https://doi.org/10.1080/01402382.2025.2531711

Winning Votes and Changing Minds: Do Populist Arguments Affect Candidate Evaluations and Issue Preferences? (with Benjamin Lauderdale and Christopher Wratil)
British Journal of Political Science (2025)
Paper

Populist rhetoric – presenting arguments in people-centric, anti-elite and ‘good v. evil’ frames – is said to provide populist parties and candidates with an advantage in electoral competition. Yet, identifying the causal effect of populist rhetoric is complicated by its enmeshment with certain positions and issues. We implement a survey experiment in the UK (n≈9,000), in which hypothetical candidates with unknown policy positions randomly make (non-)populist arguments, taking different positions on various issues. Our findings show that, on average, populist arguments have a negative effect on voters’ evaluations of the candidate profiles and no effect on voters’ issue preferences. However, populist arguments sway voters’ issue preferences when made by a candidate profile that voters are inclined to support. Among voters with strong populist attitudes, populist arguments also do not dampen candidates’ electoral viability. These findings suggest that populist rhetoric is useful in convincing and mobilizing supporters but detrimental in expanding electoral support.

Kollberg, M., Lauderdale, B., & Wratil, C. Winning votes and changing minds: Do populist arguments affect candidate evaluations and issue preferences? British Journal of Political Science. https://doi.org/10.1017/S0007123425000201

United in Success, Fragmented in Failure. The Moderating Effect of Government Satisfaction on Affective Polarization between Coalition Partners (with Jochem Vanagt)
European Journal of Political Research (2025)
Paper

Coalition governments are said to make voters of coalition parties feel more warmly towards supporters of their coalition partners and, hence, reduce affective polarization. However, even countries frequently governed by coalitions commonly experience high levels of affective polarization. We argue that for coalitions to reduce affective polarization, they must be perceived as successful. In coalitions that are perceived as unsuccessful, voters will not develop an overarching coalition identity. Such coalitions fail to change whom voters consider as their in‐group, therefore not mitigating affective polarization. We test this argument using the Comparative Study of Electoral Systems data. We find that the positive effects of coalition membership reported in previous work are exclusively driven by voters who are satisfied with the coalition’s performance. Coalitions have no depolarizing effect among voters dissatisfied with their governing performance. These results question whether democratic institutions themselves can mitigate affective polarization and instead demonstrate the responsibility of elites to make inter‐party cooperation work.

Vanagt, J., & Kollberg, M. (2025). United in success, fragmented in failure. The moderating effect of government satisfaction on affective polarization between coalition partners. European Journal of Political Research. https://doi.org/10.1111/1475-6765.70012

Does Mainstream Populism Work? Populist Rhetoric and the Electoral Fortunes of Mainstream Parties
Political Science Research & Methods (2025)
Paper

Much work is concerned with the effects of mainstream parties accommodating the positions of populist radical right parties. Little is known about the role of political rhetoric in mainstream party responses to radical right challengers though. This is a significant gap given the evident shifts in mainstream party discourse across European democracies. Using a pre-registered survey experiment in Germany, I analyze how voters react when mainstream parties engage in populist rhetoric and adopt radical right issue positions. Theoretically, I propose that voters, particularly those with populist attitudes, may use populist rhetoric as a heuristic when evaluating parties. I find that, in line with spatial theories of voting, voters penalize or reward mainstream parties based on their adoption of radical right positions, but that the use of populist rhetoric does not significantly impact voter evaluations. These findings demonstrate the relevance of programmatic party strategies in mainstream-challenger competition and cast doubt on the effectiveness of populist rhetoric.

Kollberg, M. (2025). Does mainstream populism work? Populist rhetoric and the electoral fortunes of mainstream parties. Political Science Research & Methods. https://doi.org/10.1017/psrm.2025.14

The Challenger Advantage — How Challenger Parties disrupt Mainstream Party Dominance in the European Parliament
Journal of European Public Policy (2024)
Paper

Under what conditions can challenger parties disrupt mainstream party dominance in democratic institutions? While extant work describes the cultural and economic developments that benefit challengers and parties’ programmatic responses to these, I demonstrate when and how challengers exploit these conditions in their political communication. Theoretically, I posit that challenger parties have relatively stronger vote-seeking incentives than mainstream parties. These collective incentives affect individual parliamentarians’ cost–benefit calculations. Challenger parliamentarians will engage in anti-establishment rhetoric and issue-entrepreneurship when these signals are more likely to reach the voting public and pay-off electorally. I test this theory by analysing parliamentary debates from the European Parliament (1999–2016) through a novel combination of word embeddings and bespoke dictionaries. I find that challenger parties indeed pursue different communication strategies than mainstream parties. Challenger parliamentarians engage in anti-establishment rhetoric in the run-up to elections and issue-entrepreneurship during crises. This is because these factors make speeches more likely to be transmitted to voters. These results demonstrate that challengers adjust their political communication in opportune moments giving them a competitive advantage over less flexible mainstream parties.

Kollberg, M. (2024). The challenger advantage — How challenger parties disrupt mainstream party dominance in the European Parliament. Journal of European Public Policy, 31(8), 2252–2281. https://doi.org/10.1080/13501763.2024.2391510

Reports & Policy Briefs

Potenziale konservativer Narrative für den Klimaschutz
In collaboration with heimatwurzeln e.V.
Paper

Debunking the Backlash — Uncovering European Voters’ Climate Preferences (with Tarik Abou-Chadi, Jannik Jansen and Nils Redeker)
Jacques Delors Centre Policy Paper
Paper & Data

The notion of a broad green backlash is set to dominate this year’s European election campaign. Based on new survey data from more than 15.000 respondents in Germany, France, and Poland, we show that it is largely overblown. A majority of voters still wish for a more ambitious climate policy and would support a raft of concrete measures to bring down emissions. However, supporting pivotal voters in the middle will require a stronger focus on green investment and industrial policy and offsetting measures for effective but unpopular policies like carbon pricing. Parties should not waste the coming months outbidding each other over how to cater to imagined climate fatigue but compete over concrete recipes to green the economy.

Revise & Resubmit

What Works Against Populist Rhetoric? The Effects of Pluralist and Democratic Elitist Counter-Arguments on Democratic Attitudes and Vote Choice (with Julia Leschke)

Attitudes towards Identity Politics: Abstract Support, Concrete Skepticism (with Peter Dinesen, Kim Sønderskov, Matthias Avina)

Working Papers

Economic Concerns, Far-Right Mobilization, and the Polarization of Green Policy Preferences (with Tarik Abou-Chadi)

Conservative Reframing of the Green Transformation — Persuasion Asymmetries and Voter Demobilization

Misperceived Grievances: How False Beliefs About Collective Disadvantage Fuel Populism (with Heike Klüver and Anselm Hager)