Minister

One prominent theory to the decline of Ming empire, first proposed by Huang Zongxi (黃宗羲), was the removal of Prime Minister from the government structure.

The original idea of Huang was simple: Without a prime minster, all government decisions are back to the king, which results in multiple problems:

1. The king is usually not the most capable person.
2. No one could change the king if he does not perform well.
3. The actual decision of the government falls to the eunuch.
   

In the modern translation by Yi Zongtian (易中天) and others, the king both owns the country and runs it - analogous to having the CEO and the chairman of the board of directors being the same person. It may do well for a small family business, but would inevitably be inefficient and lack of external scrutiny for a multinational conglomerate.

But there are further serious implications of the theory. For those who are more familiar with European history or interested in contemporary politics, I shall give a slightly convoluted elaboration tomorrow.