Outsider Support in Latin America: Convergence in Poor Performance, Anti-Establishment Appeals, and Denialist Rhetoric

Despite clear ideological differences between mainstream parties, voters across Latin America have increasingly rejected established parties, supported outsiders, and cast invalid ballots. Why is this so? In this dissertation, I conceptualize support for outsiders and invalid voting as two forms of protest voting, ways citizens punish the establishment. I argue that convergence in poor performance, repeated and consecutive failures by different mainstream incumbents, causes both behaviors. I focus on three performance dimensions: corruption, economic management, and public service provision. Using original survey experiments in Argentina and Chile, I find that parties' convergence in poor performance increases both forms of protest voting and does so to a greater extent than policy convergence, advancing theories of party system institutionalization. With case studies, I show that outsider victories in the Southern Cone after the end of the commodities boom occurred despite parties' policy divergence, as voters responded to convergence in poor performance. I also uncover variation in public support for different outsiders, with some benefiting from a wholesale rejection of the political class, and others representing a form of renewal rooted in voters' ideological traditions with weak ties to the political establishment. I then examine how outsiders mobilize discontent. I distinguish between two types of anti-establishment rhetoric employed by outsiders: valence anti-establishment appeals, which criticize the elite's governance failures, and ideological anti-establishment appeals, which portray mainstream parties as indistinguishably neoliberal or statist. Analyzing a novel corpus of speeches from Argentina's 2023 presidential election using large language models and embedding regressions, I show that outsiders strategically combine both forms of rhetoric. I extend this analysis to Chile's 2021 presidential election. Moreover, I argue that valence anti-establishment appeals tend to increase support for outsiders across the electorate, while ideological appeals tend to mobilize voters who share the ideological critique but repel those on the opposing side. Using a survey experiment in Argentina, I find that valence anti-establishment appeals—especially those focused on corruption—boost support broadly, whereas the effects of ideological anti-establishment appeals depend on voters' prior ideological leanings. By differentiating types of anti-establishment rhetoric and demonstrating their distinct electoral effects, I advance the study of populist and anti-elite messaging. Finally, I examine voter responses to anti-democratic rhetoric from outsiders. In transitional democracies such as Argentina and Chile, candidates have increasingly employed denialist rhetoric that minimizes or justifies past human rights violations committed by authoritarian regimes. I argue that electoral punishment of such appeals requires two conditions: voters must recognize them as anti-democratic and must place a high value on democracy, including respect for human rights. Through survey experiments, I show that centrists penalize denialist rhetoric in both countries. But right-wing voters diverge: they punish it in Argentina but not in Chile. I contend that these differences depend on whether a human rights-centered collective memory of authoritarianism became politically dominant. Where such a memory took hold, as in Argentina, right-wing voters are likely to interpret denialism as anti-democratic and sanction it; where memory remains contested, as in Chile, punishment is weaker. I examine the trajectories of collective memory through comparative case studies and use focus group discussions to illustrate how voters interpret denialism and democracy. By showing that right-wing voters sometimes sanction denialism and that collective memory shapes these responses, I advance research on democratic erosion and authoritarian legacies.