“When a country is being subverted it is not being outfought; it is being out-administered. Subversion is literally administration with a minus sign in front.” ISIS has subverted western Iraq and eastern Syria because it is out-administering the Baghdad and Damascus regimes there. That is, ISIS has erected a competent bureaucratic authority covering everything from schools to waste removal which, combined as it is with repression, is secure and stable. And with that territorial security, ISIS has apparently created a central dispatch point for planning terrorist attacks abroad. Eventually, the end of ISIS can only come about when some other force out-administers it.
ISIS is the upshot of anarchy, in other words: a situation which obtains when a populated territory is without administration, so that warrior bands prevent anyone from feeling secure. The toppling of a secular Baathist regime in Iraq in 2003 and a revolt against another secular Baathist regime in Syria in 2011 reduced those countries to dust and chaos. Baathist totalitarianism, followed by such chaos, meant that only a movement equally extreme in its own right could take root and flourish in the vacuum. Thus, whatever strategy we follow against ISIS must have as its endgame a plan to out-administer it, or else anarchy will simply return and ISIS along with it.