Islamic State is a murderous enterprise based on an insane ideology. It nevertheless desires its own survival and expansion.In October, prior to the downing of the Russian jet over Sinai and the attacks last week in Paris, no serious threat to its continued existence was apparent. The US-led coalition bombing campaign was halfhearted, and Western support for Kurdish and Arab elements engaged in conflict with Islamic State was clearly intended to contain, rather than destroy, it.By its own actions, Islamic State has now altered this calculus. Why might it have chosen to do so, and what is this likely to mean for the next phase of the conflict in Iraq and Syria (and now metastasizing beyond it)? The bombings in Paris constitute the latest act in a turn toward international terrorism by Islamic State that began in the summer of this year. It claimed responsibility for a bombing of a Shi’a mosque in Kuwait on June 26. But the first really substantial evidence of this turn was the attack on July 21 on a Kurdish community center in the town of Suruc, close to the Syrian-Turkish border. This attack was clearly intended as a strike at the “underbelly” of an enemy that formed the main barrier to Islamic State’s ambitions in northern Syria.The Suruc bombing was followed in subsequent months by Islamic State acts of terrorism in Ankara against a pro-Kurdish demonstration, over the Sinai against the Russian Metrojet Flight 9268, in south Beirut against the Hezbollah-controlled Borj al-Barajneh area, and now in Paris.The tactical motivation for these attacks is fairly obvious. In all cases, the attacks are against forces or countries engaged on one level or another against Islamic State.Islamic State has lost around 20-25 percent of its holdings in the course of the last half year. But these losses are manageable. Indeed, the group has in recent weeks continued to expand in a western direction, across the desert to Palmyra and thence into Homs province in Syria. Why, then, embark on a path that risks the destruction of Islamic State at the hands of forces incomparably stronger than it? The answer is that Islamic State does not, like some other manifestations of political Islam in the region, combine vast strategic goals with a certain tactical patience and pragmatism. Rather, existing at the most extreme point of the Sunni Islamist continuum, it is a genuine apocalyptic cult. It has little interest in being left alone to create a model of Islamic governance according to its own lights, as its Western opponents had apparently hoped.Its slogan is “baqiya wa tatamaddad” (remaining and expanding). The latter is as important an imperative as the former. Islamic State must constantly remain in motion and in kinetic action. If this action results in Western half-measures and prevarication, then this will exemplify the weakness of the enemy to Islamic State supporters and spur further recruitment and further attacks. And if resolve and pushback is exhibited by the enemy, this, too, can be welcomed as part of the process intended to result in the final apocalyptic battles which are part of the Islamic State eschatology.Because of this, allowing Islamic State to quietly fester in its Syrian and Iraqi domains is apparently not going to work.The problem and consequent dilemma for Western policy-makers are that Islamic State is only a symptom, albeit a particularly virulent one, of a much larger malady. Were it not so, the matter of destroying a brutal, ramshackle entity in the badlands of Syria and Iraq would be fairly simple. A Western expeditionary force on the ground could achieve it in a matter of weeks and would presumably be welcomed by a grateful population.This, however, is unlikely to be attempted, precisely because the real (but rarely stated) problem underlying Islamic State is the popularity and legitimacy of virulently anti-Western Sunni Islamist politics among the Sunni Arab populations of the area.This is evidenced by the fact that the greater part of the Syrian Sunni Arab rebellion also consists of Sunni Islamist or jihadi forces, many of them not a great deal less extreme than Islamic State. The most powerful rebel coalition, Jaysh al-Fatah, for example, is a union between al-Qaida (Jabhat al-Nusra), the Muslim Brotherhood and local Salafi elements.As the Iraq insurgency and the Syrian and Palestinian examples show, the tendency of popular and street-level Arab politics in the Levant and Iraq is to take the form of violent politicized religion. As a result, any Western force entering Islamic State territory as a liberator would rapidly come to be considered an occupying force and would be the subject of attacks.It is possible that because of this, Western policy will continue to follow the path of least resistance, as evidenced by the French bombing of Raqqa this week. Such bombings may serve to sate an understandable feeling of rage and desire for revenge on the part of the French public, but they will do little to degrade, much less dislodge, Islamic State.Islamic state is part of a larger process whereby Iraq and Syria have collapsed and fragmented into their component parts, and vicious sectarian war among their ruins is taking place. If Western policy- makers conclude that even given the continued existence of this larger process, Islamic State is a particular manifestation that must be wiped out, and if they seriously wish to pursue this policy, how might it be achieved, given the determination to avoid a Western ground invasion for the reasons noted above? The answer is through the effective partnering with reliable local forces, who could be persuaded, bribed or induced to undertake the military task of destroying Islamic State, in cooperation with Western air power. The obvious candidates to undertake such a task would be the powerful Kurdish military organizations in both Iraq and Syria, presumably with a leavening or decoration of Arab fighters (Sunni Arab tribal forces in Anbar, small Free Syrian Army-associated groups in Syria, and so on) for appearance’s sake and for holding the area following the destruction of Islamic State.Kurdish successes in cooperation with US air power in both northeast Syria and northern Iraq provide the blueprint for such a path.The problem here, of course, is that the Kurds, reliable as they are, have little or no motivation for risking the lives of their fighters in the probably thankless task of providing the backbone for a ground assault on Islamic State.This problem is not insurmountable, but it would require a strategy able to provide sufficient political inducements for the Kurds. This would almost certainly have to include support for Kurdish statehood or a very entrenched version of “sovereignty- minus.”Turkish concerns would of course become a factor here. Syrian-Kurdish agreement to remain east of the Euphrates seems to have calmed Ankara, for now. But Turkey’s agenda in Syria, and in particular the problematic support offered by Turkey to jihadi elements there, remain a factor awaiting attention.What is most urgent is a clear understanding that both Iraq and Syria as unitary states have ceased to exist, that part of a successful strategy must include thinking about what replaces them, and that the way to challenge the negative elements active among their ruins is by supporting the positive elements.The weeks ahead will indicate whether such a strategy is in the process of being formulated.