I don't really care this much, really.
I have confidence in these guys as far as international terrorism goes.
I'm all for it. As long as we spend our dollars on the killing, and not the occupying and nation-building.
We could have invaded and pacified the ME 2-3 times over, for what the occupation of Iraq and Afghanistan for over a decade cost. And if leaving causes a Daesh/Al Quieda eruption? Then just go in and kill them again, then leave.
Lather, rinse, repeat. Go back in 1.5 to 2 years and do it again if we have to. Eventually they'll run out of combat-aged radicalized males. Then maybe there'll be peace for 20 years or so.
And we'd have a very finely honed military that would have everyone else on Earth quaking in their boots, and it wouldn't be worn down, logistically, monetarily, or morale-wise by the occupation, and the toll of asymmetric persistence warfare.