The Court Didn’t Move: Polarization and the Reordering of Trust in Brazil’s STF, 2008–2023

Abstract

Between 2008 and 2023, public trust in Brazil’s Supremo Tribunal Federal (STF) underwent a complete ideological reversal. The far right, which expressed the highest trust in the court before 2019, expressed the lowest by 2023, and the far left moved in the opposite direction. This thesis asks whether that reversal reflects a change in what the court was actually deciding, or whether it was constructed by political forces external to the court’s jurisprudence. Three independent analyses address the question. First, pooled OLS regressions on five waves of LAPOP survey data, run across eight Brazilian institutions, show that the antisymmetric trust reversal is unique to the STF and the presidency. Congress, the police, the military, local government, and political parties all operate in the same political environment but show no comparable inversion. Second, a body of 2,302 STF plenary decisions from 2012 to 2023 is scored on a 1–7 conservative-to-progressive scale using few-shot LLM annotation calibrated against seven anchor cases drawn from the Brazilian judicial ideology literature. The aggregate case ideology score stays close to the neutral midpoint across the entire period, and an ideological proximity test finds no significant relationship between respondents’ distance from the court’s recent output and their reported trust under any of four window specifications. Third, a sentiment analysis of 27,000 Brazilian news headlines shows that while average sentiment toward the STF did not shift directionally, the within-month volatility of coverage rose substantially from 2019 onward. The convergence of these results is hard to reconcile with either mechanism from the literature’s diffuse–specific support framework. This thesis proposes ambient partisan alignment as an explanation: judicial trust in Brazil may track the political meaning elites assign to the Court more closely than it tracks the Court’s actual behavior.