Why War?

War is any large scale, violent conflict. War grows from the almost universal tribal warfare that has occurred throughout history, to wars between city states, nations, or empires. By extension, the word is now used for any struggle, as in the war on drugs or the war on terror. It was once thought man was the only creature who fought wars, but closer observation of animal life has discovered wars between ant colonies and chimpanzee tribes. A group of combatants and their support is called an army on land, a navy at sea, and air force in the air. Wars may be prosecuted simultaneously in one or more different theatres. Within each theater, there may be one or more consecutive military campaigns. A military campaign includes not only fighting but also intelligence, troop movements, supplies, propaganda, and other components. Continuous conflict is traditionally called a battle, although this terminology is not always applied to conflicts involving aircraft, missiles or bombs alone, in the absence of ground troops or naval forces. A civil war is the use of force to resolve internal differences.

In War Before Civilization, Lawrence H. Keeley, a professor at the University of Illinois, calculates that approximately 90-95% of known societies engaged in at least occasional warfare, and many fought constantly. A war may begin following an official declaration of war but undeclared wars are common. Any general theory of war must explain not only war but also peace. It must explain not only the wars fought in almost every generation in almost every country in the world, but also the rare instances of extended relative peace, including the Pax Romana and the peace in Europe since World War II.

Motivations for war may be different for those ordering the war than for those undertaking the war. For a state to prosecute a war it must have the support of its leadership, its military forces, and the population. For example, in the Third Punic War,[5] Rome's leaders may have wished to make war with Carthage for the purpose of eliminating a resurgent rival, while the individual soldiers may have been motivated by a wish to end the practice of child sacrifice. Since many people are involved, a war may acquire a life of its own -- from the confluences of many different motivations.

In Why Nations Go to War, by Darian Domer, the author points out that both sides will claim that morality justifies their fight. He also states that the rationale for beginning a war depends on an overly optimistic assessment of the outcome of hostilities (casualties and costs), and on mis-perceptions of the enemy's intentions