Speaking in the Senate on 19 September 44 bc, in the absence of Cicero, Antony made a serious accusation: ‘When Caesar had been slain, Brutus, whom I name with respect, at once lifting high his bloody dagger, shouted for Cicero by name, and congratulated him on the recovery of freedom’. From Brutus' remark (which Cicero does not deny) Antony concluded, perhaps rightly, that Cicero was not unaware of the conspiracy. In the Second Philippic, a savagely Demosthenian reply that was never delivered, Cicero accurately quotes Antony's words and hits back with a detailed and deadly polemical retaliation: he recalls the blackest stain on Antony's ‘Caesarian’ career – his complicity in the plan to assassinate Caesar the previous year, shortly after Munda. Cicero's reminder was also a gift to Octavian, since at the time he actually published this damaging pamphlet he was already in touch with Octavian.

In his answer Cicero establishes, rightly, a connection between Antony's compromise the previous summer and the strange moment during the assassination when Trebonius, who had informed Antony about the conspiracy a year earlier, kept him out of Pompey's Curia while the others carried out the stabbing. Here Cicero expresses himself in a way that at first sight might lead one to think that Cicero himself was a witness: ‘[you] who were, we have seen [vidimus], drawn aside by Trebonius at the time when Caesar was being slain’ (Philippics 2.34).