Brazil’s Supreme Federal Court (STF) is facing its most severe internal institutional crisis in recent memory, as two of its most politically significant justices are now openly demanding sanctions and investigations against each other, injecting fresh instability into the country’s political and legal environment. The public breakdown centers on a sprawling financial fraud investigation into the collapsed **Banco Master**, whose former owner, Daniel Vorcaro, allegedly maintained close contacts with Justice Alexandre de Moraes. Justice André Mendonça, who unsealed federal police evidence in the case, is now requesting Moraes be suspended and investigated for potential graft, while Moraes has retaliated by asking the court to investigate Mendonça.