Ancient Romans used to say “si vis pacem, para bellum”, which one could rephrase as “if you want peace, prepare for war”. War has always been much more than mere fighting. It affects society as a whole even in peacetime, for example in terms of training, preparation and strategy. Carl von Clausewitz wrote that war is the “continuation of politics by other means”, meaning that war implies some transformation of mentality and the awareness that sometimes dialogue and compromise are not enough to compose litigation between two countries o two communities. However, war is no necessity.
(Image from Robert Capa: Definitive Collection)