When I was younger, I believed that an allergic reaction to, say, poison ivy, meant that poison ivy was terribly damaging to my body. It wasn’t until much later that I learned that the poison ivy, while certainly not good for me, wasn’t really the problem. The problem was that my body was overreacting to the poison ivy and that most of the symptoms were my own immune system going absolutely crazy. Almost all of the damage inflicted by allergies comes not from the substance itself, but from the reaction within the body.
Terrorists cannot hope to achieve a military victory in the traditional sense. They are almost invariably, a relatively small, poorly trained, and poorly equipped group of fanatics. Their goals, whatever they are, cannot be achieved on the battlefield. No matter how effectively they strike their foes, they cannot hope to succeed without their enemies doing the majority of the damage to themselves.
I despise arguments that seek to persuade by stating “If X happens, then the terrorists win!” This is an emotional appeal that is meant to make the other party seem to be siding with the terrorists if that party continues to disagree. More importantly, I’ve never known anyone who makes this kind of argument to have taken any time to step back and consider what a terrorist “victory” would look like. If they were to actually think about it, they might come to some conclusions which would make them very, very uncomfortable.