This article examines the relationship between power fluctuations in the elite power system and the frequency of war. A theory is developed and tested using a new dataset of elite powers and elite power wars. The theory posits that fluctuations in the elite power system are related to war among elite powers due to an increase in uncertainty that accompanies such fluctuations. The theory is logically extended to contend that as elite power systems age (move temporally away from the point of fluctuation) the frequency of war will decrease, due to the decline of uncertainty. The theory is supported by analysis employing an existing dataset collected by Jack Levy, as well as a new elite war dataset. Additionally, in terms of the type of fluctuation and war, the study finds that as the system becomes more complex the incidence of war also increases.