war, a state of usually open
and declared armed hostile conflict between political units, such as states or
nations or between rival political factions of the same state or nation. War is
characterized by intentional violence on the part of large bodies of individuals
who are expressly organized and trained to participate in such violence. Wars
between nation-states may be fought to gain reparation for a particular injury;
to acquire a particular territory or advantage; to gain recognition of a
particular claim; or to achieve the extermination or unconditional surrender of
the enemy. Wars of considerable duration have usually been divided into "
campaigns" conducted in one area under one command for one season. These,
in turn, have been composed of " battles," in which opposing forces
come into direct contact for one or two days at a time (though battles have
tended to last longer in modern warfare). With the progress of science and
technology and consequent increases in the destructive power of armaments, war
has had an increasingly catastrophic effect on human existence.
The subject of war is treated in two articles. For the theoretical, tactical,
legal, and economic aspects, see War, The Theory and Conduct of .
For technological aspects, see War, The Technology
of , The World Wars.