This article investigates the emergence and diffusion of antipopulist mobilizations. Resembling the iconic image depicting a school of small fish chasing a big one, the Italian 6000 Sardine and the Finnish Silakkaliike (Herrings) emerged as two movements with antipopulist claims. Although the scholarship on populism is abundant, antipopulism remains mostly neglected, especially its mobilization from below. Drawing on extensive fieldwork including a groundedtheory approach applied to twenty-seven interviews with activists from these two movements, plus the analysis of offline and online organizational documents, this study shows the mechanisms—cognitive, affective and relational—of their national and crossnational diffusion, relating them to the opportunities of the context. Exploring the internal movement dynamics and actors’ perceptions and motivations, this study also contributes to the conceptualization of antipopulism from below, defining the main characteristics and the ideological underpinnings of these two antipopulist movements.
† We are grateful to the referees’ helpful comments. We thank the Cosmos Center at the SNS for the lively research environment and discussions within which this study can be located.