The day after the election was supposed to be held, Cicero addressed the Senate on the matter and Catiline's reaction was immediate and violent. In response to Catiline's behavior, the Senate issued a senatus consultum ultimum, a kind of declaration of martial law invoked whenever the Senate and the Roman Republic were in imminent danger from treason or sedition. Ordinary law was suspended and Cicero, as consul, was invested with absolute power.
When the election was finally held, Catiline lost again. Anticipating the bad news, the conspirators had already begun to assemble an army, made up mostly of Sulla's veteran soldiers. The nucleus of conspirators was also joined by senators whose profligate tastes left them perennially without funds. The plan was to initiate an insurrection in all of Italy, put Rome to the torch and to kill as many senators as they could.
Through some crafty moves of his own, Cicero knew exactly what was being planned. On November 8, Cicero called for a meeting of the Senate in the Temple of Jupiter in the Capitol, which was used for this purpose only when great danger was imminent. Catiline had the temerity to attend as well. It was in this context that Cicero delivered one of his most famous orations.
Quo usque tandem abutere, Catilina, patientia nostra? Quam diu etiam furor iste tuus nos eludet? quem ad finem sese effrenata iactabit audacia?Catiline was present when this speech was delivered. When he arrived at the Temple of Jupiter Stator and took his seat, however, the other senators moved away from him leaving him alone in his bench. Catiline tried to reply after the speech, but senators repeatedly interrupted him, calling him a traitor. He ran from the temple, hurling threats at the Senate. Later he left the city and went to the camp of Manlius, who was in charge of the army of rebels. The next morning Cicero assembled the people, and gave a further oration.
How long, O Catiline, will you abuse our patience? How long is that madness of yours still to mock us? When is there to be an end of that unbridled audacity of yours?
Meanwhile, Catiline joined up with Manlius, commander of the rebel force. When the Senate was informed of these developments, they declared the two of them public enemies. Antonius, with troops loyal to Rome, followed Catiline while Cicero remained at home to guard the city. During the battle that took place between the 2nd and 3rd orations, Catiline saw that he would lose and in consequence threw himself into middle of the Roman troops, who promptly killed him. The year was 62 BC. Cicero subsequently obtained documents and confessions of many of the conspirators, which he presented to the people.
While most historians agree that Cicero's actions, and in particular the final speeches before the Senate, saved the republic, they also reflect his self-aggrandisement – and to a certain extent envy – probably born out of the fact that he was considered a novus homo, a Roman citizen without noble or ancient lineage.