The theme of institutional dysfunction was expanded across different areas of the city as the show progressed. The second season focused on the death of white working class America through examination of the city ports. The third season "reflects on the nature of reform and reformers, and whether there is any possibility that political processes, long calcified, can mitigate against the forces currently arrayed against individuals." Burns has called education the theme of the fourth season. The writing drew extensively on his experience as a teacher. Rather than solely focusing on the school system, the fourth season looks at schools as a porous part of the community that are affected by problems outside their boundaries. Burns states that education comes from many sources other than schools and that children can be educated by other means, including contact with the drug dealers they work for.