Decentralizing electoral campaigns? : New-old parties, grassroots and digital activism

Recent studies suggest that new parties display new patterns of digital mobilization. We shed light on this debate: do new party supporters engage in online political activities to a greater extent during electoral campaigns? Do they share political images or quotes on social media, participate in political forums, or exchange political messages with their friends more often than supporters of traditional parties? No. Drawing on a post-electoral survey dataset in Spain, we find that offline extra-institutional political activities are key predictors of the level of online political engagement. Even in the context of a polarized electoral campaign and the emergence of new electoral forces such as Podemos, extra-institutional political participation drives digital activism to the detriment of institutional variables, such as turnout or partisan preferences. Thus, all parties depend on extra-institutional activists to boost their online campaigns. Since grassroots activists increasingly influence the communicative strategy of all political parties, we interpret this process within a long-term digital-based post-material transformation of the political culture, with major implications for partisan organization, mobilization, and polarization in many democracies. We contend that the overrepresentation of grassroots activists in producing and disseminating political content in social media may have favored an increase of the visibility and public support of political outsiders in several countries.