Justice Gilmar Mendes, the longest-serving member of Brazil's Supreme Federal Court (STF), said on Saturday night (Sept 19) that the main threat to the country's electoral courts "comes from within". In a post on X, without naming anyone, he suggested that members of the Superior Electoral Court (TSE), Brazil's top electoral tribunal, who act in a partisan way should consider whether they can stay in their posts. He also warned that the STF will step in and review the electoral court's decisions whenever it deems necessary.

"More serious, however, is the risk that comes from within: the politicization of the Electoral Judiciary. Whoever tries to engage the Court in partisan proselytism must assess whether he or she is fit to remain in it. And political parties and the Electoral Prosecutor's Office must closely monitor whether those conditions are present, claiming bias whenever it is established"

Mendes wrote that the TSE must show "an assertive, impartial and nonpartisan performance", committed only to the Constitution and the laws. On the role of the Supreme Court, he said it will act as a "supervisory instance", "intervening whenever necessary to preserve its own precedents and the Constitution". According to Poder360, the message means in short that the STF will override the TSE whenever it sees fit.

The Master case crisis reaches the electoral court

The TSE is currently led by two STF justices: Kassio Nunes Marques as president and André Mendonça as vice president. Days earlier, in a court session and on X, Mendes called Mendonça a "campaign dummy" and an "electoral pixuleco", a reference to an inflatable doll carried at a Sept 7 protest on Paulista avenue in Sao Paulo. The attack followed Mendonça's decision to unseal a report containing messages between Justice Alexandre de Moraes, Prosecutor General Paulo Gonet and former banker Daniel Vorcaro on the eve of the Sept 7 holiday. Mendonça denied using the court as a campaign platform and said his decision was grounded and specific.

According to Valor Econômico, the bloc formed by Mendes, Moraes, Flávio Dino and Cristiano Zanin accuses Mendonça of running the Master case, as rapporteur, with a supposed electoral interest to favor Flávio Bolsonaro of the PL party, a presidential candidate. On the other side, Mendonça, Nunes Marques and Luiz Fux voted to immediately open an investigation into Moraes over messages the Federal Police considered suspicious in his exchanges with Vorcaro, founder and shareholder of Master. Court president Edson Fachin and Justice Cármen Lúcia also voted against Moraes, and the outcome was postponed when Dino asked for more time to review the case.

Warnings on AI and foreign interference

In the same post, Mendes acknowledged the credibility of the TSE and of Brazil's electronic voting machines, but said new challenges force the electoral courts to reaffirm their impartiality in this election. He cited a report by Folha de S.Paulo saying that researchers produced 15 fake campaign ads using artificial intelligence and 13 of them were not blocked by Meta's filters. He also mentioned a reserved report by Abin, Brazil's intelligence agency, which according to the newspaper warned the TSE and the government of a "critical risk of external interference" in the election.

What comes next: the STF must resume the postponed vote on whether to open an investigation into Moraes, while the presidential race enters its final stretch with the standoff between the two courts at the center of the campaign debate. Political parties and electoral prosecutors may file bias claims against TSE justices, the path Mendes himself pointed to in his post.