Asymmetric warfare refers means something other than a large force on a large force. It includes, among other things, urban warfare and terrorism.

A few items:
First sentence from http://carlisle-www.army.mil/usawc/Parameters/02spring/gray.htm
"In American common usage today, asymmetric threats are those that our political, strategic, and military cultures regard as unusual."


From http://www.theatlantic.com/issues/2001/12/vest.htm
""Asymmetric" operations—in which a vast mismatch exists between the resources and philosophies of the combatants, and in which the emphasis is on bypassing an opposing military force and striking directly at cultural, political, or population targets—are a defining characteristic of fourth-generation warfare."



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