Social costs: wars fragment society. The countries involved all lose some or the majority of fighting age population. The countries involved experience some degree of population movement, for example, fleeing war torn areas or congregating in metropolitan areas to manufacture war material. This social movement disrupts culture within geographic areas within a country or countries.
Economic costs: countries involved either have their economies severely disrupted or destroyed. Severe disruption includes going into national debt to pay for war. Destroyed economies are ones in which the means of production and supply are destroyed.
Political Costs: losing countries involved are likely to see their political structure destroyed or minimized.. Winners usually see a significant change immediately after war, for example, Churchill of England was replaced just after World War Two---the winner goes in another political direction. Also, winning countries governments' may have, due to the war, acquired more social control over their populations. The losing countries, having lost their political structure, may resort to anarchy.