For invective to be effective, several conditions have to be satisfied. First of all, the designated victim has to be an established part of the community, so as to be exposed to its assault and marginalized. Secondly, as we have seen, the orator must possess the skill to manipulate the audience’s emotions; and thirdly, the audience must be won over to his side and conspire with him against the victim. In order to achieve this, the orator has to be able to exploit biases already present in his audience: ‘‘within each instance of abuse reside values and preoccupations that are essential to the way a Roman of the late republic defined himself in relation to his community’’ (Corbeill 1996: 5).
The representatives of this community, that is to say the invective’s audience, shared, according to Corbeill, elite values and preoccupations and could take different forms. In forensic speeches invective was used before a tribunal usually gathered in the Forum and dealing with either criminal or civil law. Only four of the surviving Ciceronian speeches concern civil cases (Pro Caecina, Pro Tullio, Pro Quinctio, and Pro Roscio Comoedeo), and, despite the attacks launched in these against the opponent, they do not feature the same highly colored invective as was deployed, for example, in the In Pisonem (Powell 2006). The majority of Cicero’s preserved speeches deal with criminal law and represent either the speech for the prosecution (the only surviving example being the In Verrem), the defense speech (e. g., the Pro Caelio), or the interrogation of a witness (e. g., the In Vatinium). Abusive language tended to be used most often as part of the prosecutor’s deployment of the so-called argument probabile ex vita: the more he succeeded in presenting the accused as an unworthy individual, the more probable it was that the accused was guilty of the crime under investigation. In deliberative (or political) speeches, invective could be employed before both the senate (e. g., In Pisonem or In Clodium et Curionem, see Crawford 1994: 227-63) and the popular assemblies at Rome (e. g., the Second and Third Catilinarian). In these cases invective features primarily as a weapon to be wielded in political conflicts. Its aim is to harm the opponent while enhancing the orator’s own prestige.
In civil lawsuits the orator’s audience was primarily the judge of the case; this relatively constrained context nevertheless gave some scope for humorous invective as the orator attempted to cast the adversary in a negative light (for some examples see Cic. De Or. 2.266, 268; cf. Fantham 2004: 198). But it was the large audiences at major criminal trials that provided the best opportunity for spectacular invective fireworks. As Cicero notes (Inv. Rhet. 2.32-7), it is not enough for a prosecutor simply to demonstrate the accused’s motive and opportunity for committing the alleged crime; he must also show that the man has a correspondingly wicked character. And even if the prosecutor fails to do so, he should still produce whatever negative evidence of the man’s character he can since any such details will weaken the defense (see Craig 2004: 192-4).
Cicero’s invective is especially virulent, however, in his senatorial speeches. In this respect it is interesting to compare his violent attack on Piso and Gabinius in the senate on his return from exile (Red. Sen. 10-18) with the simple mention they receive in his speech before the people on the same occasion, where they are referred to almost courteously (Red. Pop. 11, 13). Different audiences called for different strategies, although it is perhaps difficult to generalize. A speaker’s tactics were probably determined by a number of variables, including his immediate assessment of the audience’s mood and sympathies. In De Lege Agraria 2, for example, delivered before the people, Cicero accuses Rullus, tribune of the plebs in 63 and proposer of a land distribution, of acting like a tyrant (2.20-1, 75, 116-17; see Dunkle 1967). These serious accusations are then extended to the agrarian commission of decemvirs who are depicted as odious kings trying to deprive the Roman people of their sovereignty (2.22, 33-4). In this case, however, Cicero avoids extensive use of wit and abuse - an interesting decision since his most amusing examples of wit recounted in De Oratore are drawn from contiones (2.227, 230, 240, 264, 267). As Fantham (2004: 208) suggests, perhaps he could not employ humor when confronted with (to his mind) serious and substantial issues; the proper material for laughter was ‘‘trivial absurdities of dress or social foibles,’’ not ‘‘real evil.’’