Exprimer son identité en ligne : Variations gauche-droite et transnationales dans l'autoreprésentation sur les réseaux sociaux

Political orientations are known to be closely linked to positions on identity-related issues, whose salience and framing can vary both within and across countries. To capture patterns of issue-based self-identification and address pressing questions about identity (mis)alignment across EU countries and between Left- and Right-leaning user groups, we study Social Media profile bios from Twitter/X, where individuals present themselves. Our analysis combines Structural Topic Modeling seeded with Manifesto Project data, and Ideology Scaling calibrated with political expert survey data. The proposed approach allows us to study how more than 1.2 million individuals from eight EU countries self-identify with political issues across the Left-Right ideological spectrum. We find that issues such as democracy, national way of life, and decentralization emerge as the most divisive at the EU level. Other issues, such as environmentalism, equality, and freedom & human rights, among others, strongly differentiate how Left- and Right-leaning individuals communicate their identity online at the EU level. Interestingly, we also find that user groups on the Left side of the political spectrum express their identities more similarly across European countries than those on the Right. This pattern is particularly evident for identity-issues related to national way of life, suggesting that the growing international coordination among conservative parties is not (yet) accompanied by an alignment of Right-leaning users' communicated identity across the targeted EU countries. Finally, we show that our Left-Right identity similarity metrics are inversely related to country-specific perceptions of political conflict, as measured by the PEW survey. Our findings provide a major contribution to comparative political identity studies, enabling a qualitative and quantitative characterization of the EU identity puzzle and offering empirically grounded insights for better understanding identity-related mobilization on Social Media, both within and across countries.