Welcome to the paradoxical world of counterinsurgency warfare -- the kind of war you win by not shooting.
The objective in fighting insurgents isn't to kill every enemy fighter -- you simply can't -- but to persuade the population to abandon the insurgents' cause. The laws of these campaigns seem topsy-turvy by conventional military standards: Money is more decisive than bullets; protecting our own forces undermines the U.S. mission; heavy firepower is counterproductive; and winning battles guarantees nothing.
Read the whole thing. Follow it up with some Q&A.