Rooting for whom? (Former) pillar parties' group appeals strategies on social media in Belgium

Party landscapes across Europe have been characterized by the decline of traditional -or historical- political parties. They have faced successive challenges, from profound changes in the class structures of society and secularization to membership decline and digitalization of campaign and organizations. Consequently, they have suffered from their ideological convergence (or de-ideologization) and partisan dealignment. The cartelization of traditional party organizations is often pinpointed as an adaptative or resilient strategy. Nevertheless, this cartelization along with the multiple contemporary challenges, makes it more and more complex for traditional parties to differentiate from their competitors, but also from one another (Garzia et al., 2022; Grant & Tilley, 2023) in the eye of voters. Drawing from the literature on social identity theory, organizational identity and group appeals, we unravel the strategies that traditional parties adopt in their online communication to craft their image relative to groups in society (1), partisan identities (2) and institutions (3). We rely on a quantitative content analysis of parties and party leaders’ communication in Belgium on social media (X), during both routine and campaign periods. We look at the self-characterization of mainstream parties relative to the cleavage-based groups in society they have historically represented, but also relative to the new groups they appeal to following the restructuring of the partisan landscape. We aim to assess whether parties achieve homogenous partisan identities, or to the contrary actively contribute to their further dissolution. We also aim to uncover the extent to which traditional parties (Liberals, Christian-democrats, and Socialist) present themselves as agents of the State or government – as an expression of a potential cartelization. We analyze both the frequency of appeals to groups among these parties and the type of groups they seem to emphasize (economic, community, socio-cultural etc.). Finally, we compare these traditional or ‘pillar’ parties in the two language communities (Dutch- and French-speaking), and uncover differences in their strategies, which we link to the characteristics and dynamics of the two party systems.