The process of larger national political unities breaking into smaller national fragments -- generally, to intensify ethnic, religious or economic homogeneity -- is reflected, as detailed in lecture, in All Tomorrow's Parties. The term balkanisation covers the process, as does devolution and decentralisation.
The concept, as Gibson well knows, is well-debated. What I found interesting when researching the concept for these lectures is that it is a promiscuous concept. When one side or the other finds it in their immediate interest to fragment a larger political unity, the concept is vigourously advocated as a Good. Then, when it is in the interest of each of the same sides to sustain, or create a large political unity, then balkanisation is decried as a great evil.
The result for me was that my low -- very low -- opinion of political operatives and advocacy was re-affirmed (not, God knows, that it needed it.)