The Domestic Foundations of EU Distrust: Populism, National Parliaments, and Spillover Effects

Trust in the European Union has become a central concern in debates on political legitimacy. Research on public attitudes toward European integration has long emphasized the role of domestic cues (Anderson, 1998): citizens with limited direct knowledge of EU institutions rely on evaluations of national politics to form opinions about Brussels, implying that distrust at the national level may spill over to supranational institutions (Hobolt, 2012). At the same time, populism has become a mainstream political force across Europe (Akkerman et al., 2016), increasingly shaping government coalitions and public discourse (Vittori, 2022). Existing research consistently links populist attitudes to political distrust at the national level (Van Hauwaert & Van Kessel, 2018; Palacios, 2025). Together, these developments raise a key question: to what extent do distinct dimensions of populist ideology—anti-elitism, Manichean outlook, and people-centrism—undermine EU legitimacy indirectly, through their effects on confidence in national representative institutions? This paper addresses this question using nationally representative post-electoral survey data from seven European countries: France, Germany, Greece, Italy, Poland, Portugal, and Spain. We employ structural equation modelling to disentangle three core dimensions of populism—anti-elitism, Manichean outlook, and people-centrism (Mudde, 2004; Akkerman et al., 2014; Castanho Silva et al., 2020)—and to assess their direct and indirect effects on trust in the EU. This design allows us to test which facets of populist ideology drive institutional distrust and whether their impact on EU trust is mediated by evaluations of national parliaments. By leveraging cross-national variation in institutional quality, party system configurations, and exposure to EU-related crises, we assess whether these mediation pathways display common patterns or cross-national heterogeneity. The results identify anti-elitism as the pivotal dimension in the populism–distrust nexus. Individuals with strong anti-elite attitudes exhibit significantly lower trust in national parliaments, which in turn is associated with reduced trust in the EU. In contrast, Manichean and people-centric attitudes show limited independent effects once anti-elitism is taken into account. Importantly, the strength of these mediation pathways varies across countries. Spillover effects are strongest during critical moments of EU integration, when European governance becomes more visible and politically salient.