Thick and Thin Ideological Dimensions of Electoral Competition in Latin America

Previous research has typically portrayed electoral competition in Latin America as structured along a single left-right dimension. We challenge this view, arguing instead that voters perceive ideological competition along two distinct axes: a thick left-right ideological continuum and a thin establishment versus anti-establishment dimension. We test this hypothesis in Chile, a country characterized as having the most unidimensional party system in the region. Using Bayesian Hierarchical Aldrich-McKelvey scaling and Item Response Theory models on an original three-wave panel survey, we find that left-right and anti-establishment attitudes are weakly correlated, thus constituting two largely orthogonal dimensions of ideological competition. Moreover, our typology combining these dimensions predicts vote choice in both observational and experimental settings. Additional evidence from Argentina and Brazil suggests a broader applicability of this framework. These results contest the dominant unidimensional model of ideological competition, offering a nuanced approach to understanding contemporary political behavior amid Latin America’s rising anti-establishment politics.