The problem with terrorism is that if left unrestrained, they may accomplish their political goals. Those goals are generally to let them have free reign in the

The problem with terrorism is that if left unrestrained, they may accomplish their political goals. Those goals are generally to let them have free reign in the region they're in. For example, ISIS was busy setting up their caliphate, and if we had not defeated them militarily, they'd have their own little hellhole nation to run. The amount of death such regimes can inflict on their own people is pretty significant. It doesn't even require death squads or anything like that; I was at one of Sadam's palaces and remarked to an Iraqi that the pools were empty. Well, it turns out, once Sadam fell, the water was redirected back to the local tribes. Because to punish recalcitrant tribes, Sadam would just cut off their water. (None of this means major powers necessarily ought to be getting involved in all these areas; the point is that terrorists aren't just killing people for kicks, they have a reason for the things they do and there are consequences when they're successful.)