Should We Defend Cataline, or Disdain Him (as Cicero did)?
Well, first of all, to be debated is the extremity of both options: to condemn or to defend, both denoting a firmness of either Cataline's guilt or his righteousness, as it were. Cataline was a human being, and so, as with most humans, questions of absolute blame or absolute righteousness tend to be followed by gray answers, neither black nor white.
Cicero would have us believe that the matter is black. According to him, Cataline is a conspirator against the republic and guilty of planning and attempting to carry out murder, most specifically the murder of Cicero himself. His co-conspirators are to be killed, most definitely. His actions, as Cicero would claim, are of the most unworthy and unlaudable sort. Condemnation is the choice for those believing Cicero's every word.
On the other hand, Sallust paints a grayer picture. He portrays Cataline rousing up his co-conspirators with words of unjust suffering, and presenting the question, 'Why not take the republic?', as it is currently in the hands of the optimates, who, in Cataline's opinion (according to Sallust), receive riches of which Cataline and his cohorts are just as worthy to receive.
Sallust also writes of Cataline's death in a way which is undeniably the most glorious of ways for a Roman to die: in the midst of his enemies, heroically fighting for his cause in battle. This action is not one of a coward, by any means.
But one must ask, for what was Cataline fighting? For the glory of the republic, or the glory of himself? Did he figure, 'No getting out of this now; might as well go out the right way..."?
We do not know. We were not there, and were not privy to Cataline's thoughts and motivations.
However, Sallust wrote also of Cataline's plans to not only set fire to parts of the city, but also to carry out strategic murders. This is perhaps not a sign in his favor.
However, one must also bear in mind that this is not a unique strategy; it had been done before and would be done again in the bloody history of Rome, and the question of praise or dishonor rested almost solely upon whether each specific upriser succeeded in his coup d'etat. Therefore, we cannot know how differently history would have remembered Cataline, had he succeeded in overthrowing the government leaders of his time.
I personally feel that he was a strong and charismatic man, and likely very intelligent. He stayed true to his course of actions, which indicated a sense of honor. He strove for power, and probably highly out of his own interest, but such was often the way of the world in which he lived. In today's world, we would almost certainly condemn his actions, were they to happen today, but I suspect that, in his own time and were he to have succeeded, he might have been honored greatly rather than vilified. The matters are uncertain, and certainly not simple. In the end, I do not believe one can choose in certaintly merely condemnation or glorification for Cataline.