Negative selection, in politics, is a process that occurs in rigid hierarchies, most notably dictatorships. Politics is the process by which groups make decisions. ... A hierarchy (in Greek: , it is derived from -hieros, sacred, and -arkho, rule) is a system of ranking and organizing things or people, where each element of the system (except for the top element) is subordinate to a single other element. ... A dictatorship is an autocratic form of government in which the government is ruled by a dictator. ...

The person on the top of the hierarchy, wishing to remain in power forever, chooses his associates with the prime criterion of incompetence - they must not be competent enough to remove him from power. The associates do the same with those below them in the hierarchy, and the hierarchy is progressively filled with more and more incompetent people.

If the dictator sees that he is threatened nonetheless, he will remove those that threaten him from their positions - "purge" the hierarchy. Emptied positions in the hierarchy are normally filled with people from below - those who were less competent than their previous masters. So, over the course of time, the hierarchy becomes less and less effective. As this happens relatively often, once the dictator dies, or is removed by some external influence, what remains is a grossly ineffective hierarchy.