What is the main conflict in Shikasta: Re, Colonised Planet 5: Personal, Psychological, Historical' by Doris Lessing?

Shikasta is one of the colonies of the galactic empire Canopus, and is shared with a friendly empire named Sirius and a hostile empire known as Puttiora. It functions largely as an allegory for earth. The book covers Shikasta's history, from the beginnings of sentient life all the way until the mythical Third World War, where humanity mostly destroys itself. In fact, the book is subtitled, "Personal psychological historical documents relating to visit by Johor (Gerge Sherban) Emissary (Grade 9) 87th of the Last Period of the Last Days". The book has an unusual structure. It reads as a loosely tied-together series of reports ranging over hundreds of thousands of years. Some are reports from historical archives, and others are reports from emissaries on the surface and human records. The story contains many religious elements, mostly from the monotheistic traditions.