What is the main conflict in Waiting for the Barbarians by J. M. Coetzee?

One of the novel's main conflicts is centered upon the magistrate's return from the village, and his subsequent imprisonment for his "alleged" conspiracy with the barbarians. As a result, the magistrate becomes a victim of the system he once represented. He is kept in prison without trial, tortured, and eventually released. After a mock-up execution he is set free, but not allowed to work he leads the life of a vagrant and a beggar.