Sphere sovereignty is when a group of people in a certain area have special rights or power to do certain things in that area. It's like having your own little kingdom. The group of people decide how everything in their sphere will be run and make their own rules and laws. This could be something like a Native American tribe deciding how to use their land, or a group of people in a town deciding how to manage their water supply. Sphere sovereignty is important because it lets people make their own decisions about how to run their lives.