A theory of the origin of the state

I always wonder what caused the emergence of the state. The answer to this question has an important implication to poverty reduction in developing countries because one of the biggest causes of underdevelopment is state failure (the best example of this is Somalia).

Google search takes me to an interesting theory proposed by an anthropologist named Robert L. Carneiro in his 1970 article. In a nutshell, the state emerges in agricultural land surrounded by mountains, seas, and deserts. In such an area, when all the cultivable land is cultivated, villages start fighting each other to conquer more pieces of land to sustain the population. When the conquerors rule the conquered, there is a need to create the administrative structure. This is the origin of the state.

But this theory was proposed 40 years ago. There must be a refutation to this theory, or some refinement to this theory by now. If I learn those, I will write a sequel to this post.