The Oxford English Dictionary defines economic warfare or economic war as involving "an economic strategy based on the use of measures (e.g. blockade) of which the primary effect is to weaken the economy of another state". In military operations, economic warfare may reflect economic policy followed as a part of open or covert operations during or preceding wartime. Economic warfare aims to capture or otherwise control the supply of critical economic resources so that the military and intelligence agencies can operate at full efficiency or deprive enemy forces of those resources so that they cannot function properly.
The concept of economic warfare is most applicable to conflict between nation states, especially in times of total war - which involves not only the armed forces of an enemy nation, but mobilization of that nation's entire economy towards the war effort. In such a situation, causing damage to the enemy's economy directly damages the enemy's ability to fight the war.
Clear examples of economic warfare occurred during World War II when the Allied powers followed these policies to deprive the Axis economies of critical resources. In turn, the Axis powers attempted to damage the Allied war effort via submarine warfare and through the sinking of supply ships carrying supplies, raw materials, and essential war-related items such as food.