This film is not understandable outside Italy if you do not have a strong artistic sensibility, and a good cinematic culture. From the reviews I read it seems that even many Italians do not fully understand the meaning, proof of the vanity that persecutes my people.
Scipio is an irreproachable man. He has fought Hannibal since he was little more than a boy, and defeated him in Zama when he was now a man. He dedicated his life to the salvation of Rome, Rome recognizes and honors him. Perhaps too much for Cato's taste.
For Cato, Rome is a utopian republic, driven by great ambitions, but made up of small, simple, frugal people. In this republic Scipio is too much, it would be enough for him to make a sign to become the absolute master, qualities and references are not lacking.
Cato must make a laughingstock of Scipio, to make it smaller, bring it back up to everyone, in the mediocrity that characterizes the salvation of the republics.
He insists on the fact of the 500 talents precisely in this sense: he wants Scipio to admit that he is a political thief like everyone else, so that the people no longer recognize him as the imperial eagle for Rome, but as the usual leader who gets rich at the expense of the people.
For Cato Rome is in danger, there is the influence of the Greek colonies in southern Italy just conquered, with their individualistic philosophy, which is undermining the Roman mos maiorum, the sense of the state as supreme entity, the good of the state as the only one purpose of every action of a Roman citizen.
The world he helped create is crumbling in his hands. He insists that Rome's attentions are only for Carthage (now tamed and obedient), to divert the curiosity of the Romans from the softness of Hellenic culture.
Scipio then, famously known as part of a family that has always appreciated Greek culture, becomes an enemy twice.
Cato immediately realizes that Scipio the African is not guilty of the theft, but this is certainly not a relief. He also understands that Scipio is not willing to take power by force, but this is not a security for the future.. He has to cut down the only tree left standing in the forest, a tree that is too lush, very straight and without imperfections.
To achieve that result, that tree-Scipio gave up everything else: family affections, the love of his wife, friends, his town which he could not enjoy for decades.
He thought he had esteem and honors in return, but instead he finds only political disappointments and quarrels.
So he leaves the world he has saved: "Ungrateful Rome, you will not have my bones".