[peterloo]

"Asymmetrical warface", as skybird pointed it out, is the key of failure of USA

The USA, after the Korean war and the Vietnam war, after paying heavy price in terms of blood and money, seemed not to know the effectiveness of this type of warfare.

The Soviets invaded middle east in 1980s, again, a superior army defeated by a small group of Islamic militants, armed with light weapons only

Asymmetrical warface, as what its name suggest, is a type of warfare employed by small group of mobile units against a group of immobile yet superior army

In Korean war, the Chinese successfully turned the tide of battle, neutralized the USA superiority in tank and man, and the USA lose ground slowly as its supply lines disrupted, morale reduced, and death toll mounting.

The same story goes for Vietnam. The USA supply line is always ambushed by Viet Cong irregulars, armed by light weapons (the heaviest weapons used are mortars), and the USA left Vietnam in a hassle in early 70s.

The same story is going to repeat itself, I'm afraid. Although USA has better technology, low tech but adaptable IED always kills. A pound of fertilizer hidden in bulk of trash = life of several people in a squad. Comparing the cost of fertilizer and the training cost of a USA soldier and its benefits, you see the difference. Most worrying is that, the remaining soldiers left behind by the explosion must be suffering from great psychlogical stress, which kills.