The Catilinarian Conspiracy did more than show the violence that can arise when citizens are not willing to accept the results of an election. Violence itself is often employed by the state in its response to the threat of conspiracy, or simply, perceived conspiracy. Undoubtedly, Catiline was up to something suspicious; the fact that he was defeated at the head of an army hostile to the Roman government suggests that his designs presented a serious threat to Rome. However, the legal handling of his co-conspirators who were captured in Rome before they could meet up with Catiline raised basic questions about Roman justice. A fundamental aspect of Roman law, which has been long admired, was the idea that a Roman accused of a crime was entitled to a trial. During the Catilinarian Conspiracy, however, the Roman senate had passed a Final Decree, just as it had against Gaius Gracchus and Saturninus, permitting Cicero, as consul, to execute the conspirators captured in Rome without a trial.

In the senate meeting that debated the fate of the conspirators, famously recorded by Sallust, the senate favored executing the conspirators until Julius Caesar rose to speak. Caesar opposed execution, and as Rome had no prison system, he argued for the milder sentence of spreading the conspirators around Italy in virtual house arrest. Caesar was convincing, basing his argument on the Roman disinclination to put Roman citizens to death, certainly not without a trial. Caesar was opposed on this occasion, as on so many others, by Cato. Cato spoke persuasively in favor of executing the conspirators, arguing that the conspirators were now enemies of Rome, the city was still under threat, and the defense of the Republic was the greatest good. Although Cato won the day and the senate voted for execution, the Catilinarian Conspiracy was not Cato's finest hour. Cato would go on to be an outspoken critic of Caesar's authoritarianism and aberrations from the Roman constitution; he defended institutions and the rule of law at a time when few were willing to do so. However, his eagerness to oppose Caesar and his harshness toward fellow Roman citizens put him on the wrong side of history this time.