Studies focusing on national welfare states and the dynamics of how the varieties of national solidarity developed emphasize how the social fabric of national communities is seminal. The willingness of individuals to support the provision of public goods and redistribution is influenced by the notion of sharing these benefits within a political community characterized by a "common fate" (Johnston et al., 2010). Beyond this, scholars often argue that the national configurations observable in policies (i.e. the extensity and intensity of the policy) are related to conceptualizations of the community (Banting & Kymlicka, 2017; Miller & Ali, 2014). Notably, Miller argues that individuals' perceptions of the community fundamentally shape their choice of key justice principles—equity, equality, and need—which subsequently influence their support for solidarity policies within the community in question (Miller, 2001).
To date, there has been no empirical investigation into the validity of this argument within the context of the European Union. While numerous recent studies have highlighted the significance of European identity in fostering institutionalized solidarity within the EU, no study has so far considered how the community framing of the EU shapes preferences for solidarity policies at the supranational level. To address this research gap, we employ a survey experiment conducted in Spain. Our study aims to analyze the impact of distinct notions of the EU community on support for institutionalized solidarity policies at the supranational level. Additionally, based on the work of Imai et al. (2013), we examine how justice principles function as a mediator between notions of EU community and support for European solidarity. Furthermore, to verify the generalizability of the experiment, we also analyze the TESS dataset conducted in 2016, and show that the same associations can be identified for samples from the general population of 13 European countries.