The New York Times is reporting Isis increasing in strength again.
Yes, I know. They were “defeated.” Unfortunately, with an organization like that “defeated” is not enough. You need “eradicated.”
Many years ago I read the “prequel” to Elizabeth Moon’s Deed of Paksennarion, the book Surrender None. One of the “lessons” the protagonist by the name of Gird got from his mother was when cleaning a milk bucket you had to get every last bit of the old spoiled milk out or the new milk would quickly spoil.
In the story Gird had no idea why that was. We, of course, are well aware of the germ theory of disease and how the microorganisms in the residue will quickly multiply in the fresh milk leading to quick spoilage. In the book Gird uses that as a metaphor for other things. You have to completely fix a problem or it will come back to haunt you.
That metaphor applies equally well today.
With something like ISIS, you have to completely eradicate them, or at the very least deny them any place where they can retain any kind of force or they will grow back the moment you turn your back. There is no “safe levels” of ISIS that you can dismiss and ignore. Ignoring even a remnant, leaving it alone, will be interpreted as a “victory” on their part in their minds and they will have no shortage of others willing to be convinced that it was and thus will be willing to swell their ranks.
And then you have it to do all over again.