This article provides the conclusions of a study of wars which are relatively well-documented through the ages and across the continents of human settlement. The evidence on which these conclusions are based is to be found in my book On Wars published by Yale University Press in July 2023. There are two main conclusions. First, the initial decisions to make either war or peace have almost always been made by a small handful of rulers and their advisors, regardless of whether they inhabit autocratic or representative political systems. They are to blame for war, not the peoples. Second, wars are rarely rational in either means or ends. They are rarely carefully calculated and they rarely bring the the desired ends, with the exceptions of where big powers aggress against small ones, “sharks swallowing minnows”, and of wars fought in self-defense where there is a reasonable chance of success. This is because in addition to the element of rational calculation so stressed by Realist theory, rulers and their advisors are substantially driven by combinations of emotions and ideologies.
