yustr hits the major point... we have to keep that major population happy. If you spit on them, be prepared to be spit back upon.
The rules of war are set to help protect those that do not participate. If my country gets invaded and I do not participate I would expect to be left alone.
Now sometimes mistakes happen. A bomb goes off target, or you get wrong intelligence it happens, its expected. But it should not be done on purpose.
We do blow up IED laden vehicles. Thats actually standard operating procedure. Blow it up in a controlled setting so that it does less damage.
With the Laws of Armed Conflict described in detail here
http://usmilitary.about.com/cs/wars/a/loac.htm
Its dual protection.
If you blow up a hospital on purpose you are going to get prosecuted. If that hospital has an anti aircraft gun on the roof, that hospital loses its protection under LOAC and therefor can legally be bombed. However military neccessity might deem it a low priority.
And csc... we invaded Afgahnistan because we wanted OBL... so what conner said still rings true
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