An elaborate sting was devised. The Allobroges were asked to obtain documentary proof of the conspiracy by persuading the conspirators to write letters to the tribe’s Senate. They did so, also sending along a messenger, a man from Croton, with an unsigned communication for Catilina, whom the Allobroges were invited to visit on their way home. In addition, the messenger was given a word-of-mouth recommendation that Catilina should commit one of the most heinous offenses in the Roman catalog: the freeing of slaves to take up arms against the Republic.
The Allobroges left Rome on the night of December 2 and ran into an ambush, led by the Praetor Caius Pomptinus, which Cicero had laid at the Milvian Bridge across the Tiber just outside the city. Everyone was arrested and brought back to the city. Here, at last, was all the evidence that could be desired. Cicero convened the Senate early the following morning, aptly enough at the Temple of Concord at the foot of the Capitoline Hill.
Most of the day was taken up with hearing the evidence and receiving reports. The man from Croton was given immunity, and he testified. Four Senators took down verbatim notes at the Consul’s request, so that a full and accurate record of the debate would be available. (Cicero arranged for clerks with shorthand skills to attend future sessions.) The house of one of the conspirators, Caius Cornelius Cethegus, was found to be stacked with weapons, spears, armor and a large number of knives and swords. Lentulus, as a senior magistrate, underwent some sort of cross-examination. He resigned his office as Praetor, taking off his purple-bordered toga on the floor of the Senate and putting on other clothes more in keeping with his new situation.
It was a cut-and-dried case. The leading conspirators were handed over to the Praetors to keep them under arrest, although not in chains, and there was a scare when slaves and freedmen of Lentulus and Cethegus came around by back streets to the Praetors’ houses and tried, unsuccessfully, to rescue them. Cicero left the debate briefly to station guards in appropriate places in the city.
In the evening dense crowds gathered outside the Temple of Concord and, when the Senate adjourned, Cicero came outside to make a short speech to the crowd: he made the most of the horror stories about firing the city, freeing the slaves and inviting a Gallic invasion. Large numbers of people then escorted him to a friend’s house where he spent the night. He was unable to go home, for Terentia was presiding, as the Consul’s wife, over a secret ceremony in honor of the Good Goddess in the presence of the Vestal Virgins, from which men were forbidden. Those attending the ceremony were well aware of what was happening outside; when a flame suddenly shot up from a dying fire on the altar, it was immediately interpreted as a portent and a message was sent out to Cicero advising him to take action against the conspirators.
What should be done with the prisoners? In principle, as Roman citizens, they should receive a trial, but that would entail a dangerous delay while Catilina was in the field. The mood in the city was volatile, and the likelihood of bribery would make the outcome of any court proceedings uncertain, however strong the prosecution’s case. The alternative was to execute the men without delay. This was both legally and politically problematic. The trial of Rabirius was still fresh in everybody’s mind. Caesar had used the case to limit the force of the Final Act. AS Cicero was well aware, Caesar could well organize a backlash if citizens were killed without a proper hearing. While a Consul had power over life and death when in office, he could be called to account in the courts after the end of his term. It could, of course, be argued that the conspirators had abrogated their citizenship by taking up arms against the state. This would self-evidently be the case with Catilina, who was at the head of a hostile army. But as for Lentulus and the others, the position was less clear-cut. They had not been caught in the act of rebellion, although the cache of weapons was damning evidence of their intentions.
Cicero decided to cover his back by asking the Senate, which met again two days later, for its opinion. He indicated that he would implement whatever they decided, although he implied that he favored execution. He called on the Consul-designate, Junius Silanus, to speak first. Silanus argued for the “extreme penalty,” which everybody took to mean death. The other Consul-designate, Murena, agreed, as did the bench of ex-Consuls. It looked as if there would be no argument. But then the Praetors-Elect were invited to speak and Caesar stood up to address the meeting.
He spoke with great severity. No form of punishment could be too harsh for the crime, he said. But the death penalty would be a mistake. The accused were men of distinction. Death without trial would create a disastrous precedent and, although he had “no fear of Marcus Tullius,” another Consul might use his power despotically. The text of his speech has not come down to us, but Cicero’s response has. In the published version Cicero is recorded as saying, “Imprisonment, [Caesar] says, was unmistakably devised as the special penalty for atrocious crimes. He moves, therefore, that the defendants should be imprisoned, and distributed among the municipalities for their incarceration.” If Caesar had indeed argued for long-term, perhaps life imprisonment, his suggestion would have been hard to take seriously in a country that did not have residential jails. How would the conspirators be looked after? Surely there would be a high risk of escape. (The previous day, after all, had seen an attempt to free the prisoners.)
According to later sources, Caesar in fact proposed that Cicero “ought to distribute the accused around the towns of Italy, as he thought best, until Catilina had been suppressed and they could be brought back for trial.” No doubt, he had in mind house arrest at the homes of local worthies. This was a more rational and practical proposition and one far more difficult to oppose. It is probably what was actually said, in which case Cicero distorted Caesar’s position in his published address. He would have had good reason for doing so, for it was not long before he needed every argument he could muster to defend the decision that was actually taken. It would help him if he could show, or suggest, that Caesar’s alternative was unrealistic.
One way or another, Caesar’s speech was a courageous and clever act. It had a decisive impact, and opinion turned against execution. Silanus recanted, saying he had meant not death but imprisonment. Only one ex-Consul, Catulus, spoke against Caesar’s proposal.
Then Marcus Porcius Cato, an influential figure still only in his early thirties, took the floor. Cato was one of the most remarkable and idiosyncratic personalities of the age. An uncompromising Republican, he was a ferocious opponent of the populares and of anyone who breached the constitution. From his childhood on he had had an obstinate nature and his name became a byword for virtue and truthfulness. “That’s incredible, even if Cato says so,” was a common expression.
AS a boy he had been “sluggish of comprehension and slow, but what he comprehended he held fast in his memory.” He had loved a half-brother, who died young, with the same almost monomaniac excess with which he adhered to his opinions. Cato had rigid views of right and wrong, and he had no sense of humor. He was impervious to physical discomfort. Apart from the fact that he was a heavy drinker, he lived austerely, sometimes not troubling to wear shoes. Although not averse to making money, he was ferociously opposed to bribery and corruption in public life. AS Quaestor in 65, he was responsible for the management of the Treasury: he reformed the lax financial procedures he found there, upsetting the civil servants and his Senatorial friends. Cicero admired him, but found him difficult to handle, mainly because he had no aptitude whatever for compromise.
Cato was a good public speaker with a loud, penetrating voice, although, unusually for the age, he did not practice rhetorical exercises or rehearse his speeches in public. Once he was on his feet he could speak for hours and was an indomitable filibusterer. On this occasion he was blunt. He attacked Silanus for changing his mind but reserved most of his scorn for Caesar. Under a popular pretext and with humane words, he said, Caesar was trying to subvert the state. He wanted to frighten the Senate about a situation from which he had a good deal to fear himself. Why was the Senate hesitating? The conspirators had confessed to planning massacres and arson. “If we could afford to risk the consequences of making a mistake,” Cato said (according to Sallust), “I would be quite willing to let experience convince you of your folly, since you scorn advice. But we are completely encircled. Catilina and his army are ready to grip us by the throat, and there are other foes within the walls, in the very heart of our city.” He concluded by putting a motion to the house: “Having admitted their criminal intention, they should be put to death as if they had been caught in the actual commission of capital offenses, in accordance with ancient custom.”