Solve? What, like eradicate completely? Not a fair question.
If Syria is ISIS HQ, it'd certainly make sense to hit them hard at home; drone training camps at the very least. Take out the head, shake up operations, seems obvious. Why is this unreasonable?
And why no "middle ground," assuming I understand correctly? What else is there?
Haven't we already been doing the things you suggest for years now? We have already bombed bases, killed high ranking officials, and eradicated pockets of resistance, yet the terror attacks keep comin.
The killing of terrorists obviously needs to continue, but we need to do something more, because we obviously arent doing enough.
I think we really need to look at closing the borders to all future refugees, and seriously consider deportation, or at the very least, heavy surveillance of the Muslims already located in the west.
After that, who cares what they do to each other, in that middle eastern cesspool .