here's some stuff to consider about this particular version of a Muslim enemy, some of my info culled from a NPR interview recently...
ISIS is not a nation, has no real designs on taking a nation in the way we define nations. They are not terrorists looking to establish a border defined state of their own for ideal Islamic life. And because of this and other factors I am going to say, it is a mistake to approach this enemy with conventional military thought.
Rather than land grabbers, this group is made up of a fanatical band of believers in an apocalytic dream (not sure if I am using the correct word "apocolyptic") and are looking to rid the world of the impure, the infidels, the trash, the enemy, the unclean, the "fill in the blank"...in the belief that it must be done for the "end" to come.
This is why they are undisturbed by the thoughts and sights of horrific murders as these are done with a joyful heart, fulfilling prophesies of some sort. I'm not remotely suggesting we accept them, but imagine believing beyond doubt that you are serving your version of the supreme will and power of the universe properly. Euphoria, no? Easy to believe that other's lives are of the devil and brutal death is deserved. Smiley faces at executions.
Land/territory is of no long lasting value. This is why they have no problem invading and demolishing cities and towns that have zero strategic value. Not because they want to take over, they want to wipe out. Oh the end will be glorious.
But because they are not identifiable by borders, because they arise from all locations, urban neighborhoods, rural areas, it is not possible to defeat them geographically. A new paradigm of warfare is required. This is not simple, their methods excite many, some are lost souls, some already believe, and recruitment comes from everywhere...including the USA.
So much for profiling.
Theorists have proposed that partly due to having no real "roots" like conventional nationalities and cultures, this movement will eventually burn out and must be battled as hot spots develop until such time as they are inconsequential...but even those who buy this plan believe that will take a very long time.