I to (most people should have realized that by now) believe as Zateel does, that if we don't do anything, they will keep killing us. There are still terrorists organisation in the US, Canada, UK, France, Belgium, Germany... We have to take them out before they take us out.
It's sad, it's going to be bloody, but unfortunately, that's the way it is. I'm not advocating here to bomb the **** out of supporting countries. We must assassinate terrorist on sight, without hurting the local population. Yes, it's going to be tricky because you don't know exaclty who they are until they strike. Which means that, most likely, innocents will die in the process.
Personnaly, I do not believe in bringing them to justice. Plus, in trial, they will most likely get away by claiming some sort of religious rule (expecially if they have the writings to prove it) or insanity. If we, as a free society, can let Jehovah Witnesses (I'm just making this point as sake of demonstration, I'm not targetting Jehovah Witnesses) child die when in need of a blood transfusion, I don't see why we would have a problem with granting them the right of self defense (yep, that's how screwed up our system is)