Persistent Advantage? Radical right and mainstream MEPs’ Communication on Immigration, 2014-2024

Immigration has consistently ranked as a top-priority concern among European citizens over the past decade and represents a core issue for radical-right and sovereigntist parties. Research on issue ownership (Petrocik, 1996; Walgrave et al., 2012) and niche party competition (Meguid, 2005) suggests that sustained salience on culturally divisive issues creates strategic dilemmas for mainstream parties: should they accommodate by adopting rivals’ positions, or dismiss by shifting focus elsewhere? While accommodating strategies have been documented in electoral manifestos and parliamentary speeches (Abou-Chadi & Krause, 2020), less is known about whether mainstream parties can successfully compete on owned issues in digital political communication, where audience engagement and not just message content determines visibility and influence. This paper investigates how Members of the European Parliament communicated about immigration across two legislative terms (2014-2019, 2019-2024). Drawing on an original dataset of 1.4 million Facebook posts by all MEPs, we examine whether mainstream parties have converged toward right-wing communication patterns over a decade of sustained salience on immigration, and whether any behavioral convergence translates into comparable audience engagement. The study analyzes three main dimensions: (1) the salience of immigration-related content; (2) the negative vs. positive framing of immigration messages; and (3) audience engagement (reactions, shares, comments). We compare MEPs from radical right and non-radical right parties, controlling for party-level indicators (Chapel Hill Expert Survey scores), individual characteristics (seniority, leadership roles, parliamentary responsibilities), and electoral context, including proximity to European Parliament elections and national elections in MEPs' home countries, to account for campaign-driven intensification of communication. The longitudinal design allows us to assess whether the gap between sovereigntist and mainstream MEPs in terms of communication intensity, negativity, and audience response narrows or persists across the two legislatures, distinguishing between behavioral convergence (matching communication levels) and genuine normalization (comparable audience resonance). Two research questions guide the analysis. First, have mainstream MEPs increased their emphasis on immigration relative to sovereigntist MEPs, and if so, does convergence occur gradually or concentrate around critical junctures? Second, does increased mainstream communication generate proportional gains in audience engagement, or do sovereigntist MEPs maintain disproportionate audience responses per post? By combining computational text analysis with longitudinal individual-level data, the paper contributes to debates on issue ownership dynamics under sustained salience, the limits of accommodative strategies in platform-mediated environments, and algorithmic amplification of niche party messages in European digital political communication.