Vigilantism is a real thing. In the face of social collapse, local militias form and take over the basic government functions, beginning with protection. During this natural evolution, things tend not to go well for those associated with the previous social order. You can see examples of this all over the world, wherever local militias have assumed control of a region they did not first conquer via warfare. Over time, without outside intervention, militias tend to evolve into local governments - providing other services to the community besides protection, such as law enforcement, basic welfare assistance, medical support, etc. Usually you think of war torn Africa or the Middle East when you hear of this, but it has also occurred in several farm villages in Mexico, for example, where the governments are unable to contain the power of the drug lord armies, forcing the villagers themselves to mobile and take up defensive arms. It really occurs just about anywhere, and anytime, the existing social order has collapsed. Like the White farmer's in South Africa.