War of attrition
A war of attrition is a war in which the competing sides seek to win by exhausting the enemy's resources, rather than by a decisive battlefield victory. Such wars tend to be long-lasting, with relatively static battlefronts. Probably the best modern example of a war of attrition was the conflict on the Western Front in the First World War (1914-1918); another is the Iran-Iraq War (1980-1988).
No war is by intention a war of attrition; rather, the aggressor almost invariably expects a swift victory (Germany invading Belgium and France in 1914, Germany invading the USSR in 1941, the Allies invading Italy in 1943, Iraq invading Iran in 1980, terrorists attacking the United States in 2001), and it is only once such hopes are disappointed that a war takes on an attritional character.
In a war of attrition, countries ramp up their production of arms. In addition, countries bomb the opposition's war production facilities in order to stop the enemy from resupplying. In some cases, such as WWII, key components of a country's war machine capabilities such as oil are restricted. Furthermore, various means are used to harm an enemy's economy such as economic sanctions.