The logic of preponderance of one state over the other as a pacifying condition is challenged in balance-of-power theory, which is based on the premise that two states or coalitions of states are unlikely to go to war if there is an approximate parity or equilibrium in their capabilities. According to this theory, it is usually the stronger state that goes to war in order to dominate its weaker opponents. Hegemony of a single actor is the most dangerous condition, because the hegemonic state will be encouraged to impose its will on others. When a hegemonic state emerges, weaker states, fearing domination or extinction, will therefore flock together in order to prevent conquest or domination by the stronger side. This balance-of-power logic has fundamental problems when confronted with situations in which a stronger state is content with the status quo but a weaker state becomes an aggressor due to dissatisfaction with a territorial or political order. For the weaker party to go on the offensive, however, it requires some advantage that enables it to sustain the conflict for an extended period. Although equality of capability is often difficult to measure, it is fairly accurate to argue that challengers in a rivalry dyad must have some capacity to maintain an enduring rivalry. If the power differential is too high, then logically the weaker party should eventually give up the conflict. Although there are exceptions to this general principle, they are few in number.
Two states cannot go to war if their capabilities are
