General problem of control

Governance is a control problem. We generally think of law enforcement as controlling those who are outside the ruling group, but actually control has two faces: control of outsiders and of insiders. Dual control exists in all parts of the political apparatus; nowhere is it more important than in those segments of the government that have access to armed force. Law-enforcement and military systems present the ruling group with a serious dilemma. It is necessary to develop effective users of force, to counteract those who want to do violence to the existing order, but this need must be balanced against the necessity of keeping the users of legitimate force from becoming too powerful.

The Sung were unsurpassed among the major Chinese dynasties in dealing with this problem. Their success in creating a sufficient but not excessive system of the institutions of force is reflected both internally and externally. It is often said that the Sung were militarily weak. Certainly this was true in the sense that the Sung never succeeded in retaking the area inside the Great Wall held by the Liao dynasty. Then, in the 1120s the Northern Sung was disastrously defeated by the newly powerful Chin state and survived only as the truncated Southern Sung state. Finally, in the late thirteenth century the Sung were overthrown by the Mongol founders of the Yüan dynasty. However, strength and weakness are measures not just of the internal power of a state but also of the power of its enemies.