Brazil’s Supreme Court Crisis Deepens as Justices Set to Vote on Investigating Colleague Alexandre de Moraes

The internal crisis at Brazil’s Supreme Federal Court (STF) has escalated into an unprecedented institutional conflict, culminating in an extraordinary plenary session called for Tuesday, September 15, 2026, to determine whether to open a formal investigation into one of its most powerful members, Justice Alexandre de Moraes. The decision by STF President Edson Fachin to call the high-stakes session comes as the court grapples with the fallout from an open conflict between Moraes and fellow Justice André Mendonça.

The core of the dispute involves a Federal Police report, unsealed by Justice Mendonça, that alleges an improper relationship between Justice de Moraes and disgraced banker Daniel Vorcaro. Vorcaro, the former controlling shareholder of Banco Master, is currently under arrest in connection with a multibillion-dollar financial fraud scheme. The unsealed documents include text messages that suggest Vorcaro sought advice from Moraes shortly before his arrest and mention a contract involving the banker and a law firm connected to Moraes’s wife.

The STF, which is Brazil’s highest court and the final arbiter on constitutional matters, is facing its greatest test of credibility in years. To manage the crisis, Fachin moved decisively this week, including removing Moraes from his role as the rapporteur of the politically charged ‘Fake News’ inquiry (Inquérito das Fake News). This controversial inquiry, established in 2019 to investigate alleged attacks and threats against the court and its justices, had become one of Moraes's primary tools for aggressively pursuing and ordering the arrest of political opponents, notably figures aligned with former President Jair Bolsonaro.

The September 15 session will not immediately decide whether to investigate Moraes. Instead, the court will first vote on the admissibility of the Federal Police report itself. The country’s Prosecutor-General (PGR) has argued that the report should be invalidated because Justice Mendonça ordered the evidence to be gathered without first communicating the request to the STF Presidency or the full Plenary, which is a prerequisite when the target is a sitting justice. Fachin also acted to stabilize other court procedures by suspending conflicting ministerial decisions regarding the leadership of the Federal Police, aiming to de-escalate a direct confrontation between justices over a critical national security body.

This institutional risk is the most significant measure of political uncertainty for investors observing Brazil’s election cycle. The outcome of the September 15 vote will determine whether the court can regain institutional stability or if the conflict will further erode the court’s authority. Analysts will watch to see if the STF prioritizes its internal stability by dismissing the evidence on procedural grounds or if it opts for unprecedented transparency by allowing an investigation into one of its members.

What it touches

The deepening judicial crisis adds a layer of institutional uncertainty that registers as a country risk premium for Brazil’s financial assets, particularly in the lead-up to the national election. While the immediate market reaction is tied to global flows, this type of sustained internal conflict in a core institution is a drag on investor sentiment toward Brazilian assets, including the Ibovespa index and the local currency (USD/BRL).