War generally denotes armed conflict. It can also mean sustained conflict, such as a cold war, in which the force of arms plays a highly significant part although armed forces may not come into direct confrontation. Methods of warfare include nuclear, chemical and biological, enhanced conventional as well as less sophisticated means of land, sea and air warfare, economic warfare and guerrilla warfare. Types of war include civil, international, nationalist, racial, religious and ideological. A steadily growing number of conflicts erupt within countries owing to economic, social, ethnic or religious differences and cause much damage. The repercussions of these conflicts have exacerbated the difficulties of the victims, who frequently are left unprotected since existing international legal instruments are not applicable to their situation.
Armed conflicts jeopardize and delay efforts to achieve development. There is a prejudicial interrelationship between underdevelopment and war. It is the civilian populations, and in particular children, who lose most in war in terms of suffering and death. And the consequences of an armed conflict may be very cruel for the combatants themselves and their families.
The four Geneva Conventions define armed conflicts in three different ways: (a) An international armed conflict between two or more States which are party to the Geneva Conventions of 1949 and to Additional Protocol I of 1977, whether or not the conflict is a formally declared war and even if the state of war is not recognized by one of the parties; (b) Situations in which people are fighting against colonial domination, alien occupation and racist regimes, in the exercise of their right of self-determination as one of the fundamental principles of international law by the Charter of the United Nations; (c) A non-international conflict within the territorial limits of a State, when obvious hostilities break out between its armed forces and other organized armed groups, in situations where dissident forces are in conflict with the armed forces of the State, if the former are under responsible command and exercise such control over part of the territory as to enable them to carry out sustained and concerted operations.
The history of war shows evidence of a steady growth in the role of the economic factor in war. Until the 19th Century, wars had a comparatively narrow economic base and were waged by rather small professional armies. Since the second half of the 19th century, and particularly during the 20th century, wars have strained the economy of the belligerents and involved millions of people. More than 70 million people participated in World War 1 (1914-18) and more than 110 million in World War II (1939-45).
It has been estimated that in the last 5,500 years there have been 14,513 wars in which approximately 2,640 million people were killed. In the last global conflict, the Second World War, an estimated 30 million civilians and 30 million military personnel were killed. Since 1946, approximately 137 wars have been fought, with not a single day in which there was not a state of war somewhere. Over 85 nations have been involved, that is about one-half of all presently existing nations. Over 17 million civilians have been killed, namely 50% of the World War II total, and as many as 30 million deaths in total. In 1987 there were 25 wars going on that had taken some 3 million lives. The total conflicts in 1988 was 39; in 1989, 36; in 1990, 38; in 1991, 35. The total climbed again in 1992 as wars spread through former Yugoslavia, ex-Soviet republics and in Angola. Most of these conflicts have taken place in the poorer countries of Africa, Asia and Latin America, causing many casualties, especially among civilians. At mid 1993, the estimate was 32 wars, 69 low intensity conflicts and 59 serious disputes. The UN had peace-keeping and other forces in 15 countries.
As many as 48 million people were killed or injured worldwide in the various wars fought during 1999.
The US has never had a decade without war. Since its founding in 1776, the US has been at war 93% of the time. These wars have extended from its own hemisphere, to the Pacific, to Europe and the Middle East. The US has launched 201 out of 248 armed conflicts since the end of WWII. In recent decades most of these wars have been unsuccessful. The US maintains 700 military bases or sites around the world.