Judicial Intervention at the Close of the Polls: Brazil's 2026 Presidential Runoff, Survey Discrepancies and Constitutional Accountability A Documentary and Quantitative Case Study for International Legal Scholarship

The Brazilian presidential runoff of 25 October 2026 combined a reversal between electoral rounds with an exceptional judicial order that altered the scheduled voting deadline. Flávio Bolsonaro led the first round on 4 October (47.03% to 45.16% of valid ballots), while Luiz Inácio Lula da Silva finished ahead in the runoff (51.79% to 48.21%). On election day, Supreme Federal Court (STF) Justice Cristiano Zanin granted emergency relief in Constitutional Complaint 101,673/BA and initially directed a nationwide extension from 5:00 p.m. to 7:00 p.m. A subsequent clarification limited the extension to stations that had not already closed. The Superior Electoral Court (TSE) temporarily interrupted national vote tabulation and São Paulo’s electoral tribunal later reported that approximately four-fifths of its sections had closed before regional instructions were transmitted. This article reconstructs the electoral returns, compares a defined set of contemporaneous opinion polls, traces the judicial and administrative record, explains Zanin’s prior professional representation of Lula and evaluates jurisdiction, remedy design, judicial impartiality and equal access to the franchise. Particular attention is given to international criticism without equating statements by private foreign actors with the positions of heads of state. The available evidence establishes a last-minute institutional intervention and uneven implementation but does not quantify additional votes attributable to the extension or prove that it altered the outcome. The study offers a reproducible evidentiary test for future legal and electoral inquiry.