 The parts of domestic political systems stand in relations of super- and subordination. Some are entitled to command; others are required to obey. Domestic systems are centralized and hierarchic. The parts of the international-political systems stand in relations of cooperation. Formally, each is the equal of all the others. None is entitled to command; none is required to obey. International structures are decentralized and anarchic. (Waltz 1979: 88)