Outside the system, but inside parliament: outsiders in Brazil, Chile, and Argentina

Abstract

The crisis of representation in Latin American democracies has renewed the composition of legislatures, yet the mechanisms of this process remain insufficiently understood. We examine the entry of outsider deputies into the lower chambers of Argentina, Brazil, and Chile across seven elections held between 2017 and 2023, drawing on a corpus of 406 first-term deputies. Measurement combines an additive index of six dichotomous indicators of prior party-political experience, comparable across cohorts, with the Outsiderism Index estimated through Item Response Theory, appropriate for ranking cases within each cohort. The results show that anti-system presidential leadership, electoral reforms, and critical junctures shape legislative recruitment through country-specific interactions. Presidential leadership is associated, across all three countries, with a higher share of newcomers, but only in Brazil and Argentina does a confirmed effect on the intensity of outsiderism emerge. In Chile, turnover is substantial in volume, but the change in intensity is not statistically distinguishable from zero and is concentrated in a single dimension, the absence of formal party affiliation. Outsiderism is a multicausal and substantively heterogeneous phenomenon: not only its magnitude but also its content varies across countries.