Nowadays those who start wars are even more remote and isolated from its horrors than they were in the past. So they may feel that they do not share in the personal cost. Yet this is not true. For war has invisible costs, hidden injuries, less manifest than the rapes, mutilations, deaths, sickness and starvation, yet as deadly to the civilizations which engage in war as the physical scars.
The feuding wars of tribal societies tend to create equality by keeping groups in balance. If one group gains a temporary advantage, it attracts predatory attacks from neighbours, and is returned to the average position. On the other hand, the wars of civilization have a strong tendency towards creating inequality, both between the contending groups, and within them. The immediate effect of war is to make the conquered into slaves, prisoners, permanently in thrall to the conquering power.
Another effect was that after the emergence of states, a caste of warriors, often armed knights who could afford expensive weapons, arose and dominated the rest. As a result a weak, unarmed, mass of the population was crushed by the warriors with their superior weapons and castles. War both justifies their privilege and made any questioning of their right to bear arms into an act of treason.
Furthermore the movement towards a centralized state is made much more likely by war. War against outsiders justifies higher taxes and the maintenance of a standing army. It encourages the development of a large bureaucracy to administer the state’s taxation, the suspension or elimination of civil liberties and the destruction of all those who criticize the government.
The effects of war in turning Rome from a vibrant Republic into an autocratic Empire has often been noted. Victory was as disastrous as defeat. All opposition or questioning of the State and its motives was banned. What was demanded was unquestioning loyalty, unthinking patriotism, ‘my country right or wrong’. Thus the core of liberty and equality are quickly undermined by war.