Beginning with the Cold War, as the two great power blocs confronted one another all political and cultural questions were, to greater or lesser extents, overdetermined by the stand off. As such, it asked religion which side it was on. The West was the upholder of individualism, capitalism, and styled itself as irreducibly Christian. The East was collectivist, socialist, and atheistic. Surely it would be an easy decision? From the standpoint of Eastern Europe's Stalinist monoliths, the Catholic Church was eyed with some suspicion (and, as we know from the Polish experience, they were right to be worried). Simultaneously, there were conscious efforts to rally Christianity to the banner of anti-communism. Yet there were resistances on the part of Europe's faith communities to being co-opted either way. For example, the Church of the Czech Brethren offered their own imminent critique of East and West by singling out anti-human tendencies in both systems, while declaring for neither side. There were also serious efforts at Christian/Marxist dialogues spearheaded by a number of Western Communist Parties, and the Conference of European Churches and the Christian Peace Conference worked at cross-bloc communication aiming at de-escalation.
The end of the Cold War led to a new world order, and one in which ideologues rushed in to define the new foe. In his hubristic The End of History and the Last Man, the once-notorious (and now largely forgotten) Francis Fukuyama, capitalism and liberalism were declared triumphant. Communism was gone, fascism long-dead and so we'd reached the end. There is no competitor as our way of the world had proved its superiority over all-comers. In his arrogance, Fukuyama however did note that Islamic fundamentalism presented something of a challenge, but it was one rooted by geography and could not pose as a global alternative to the West. Others were less discerning. Samuel Huntington's The Clash of Civilizations clearly located Islam as the West's new Other, a thesis that obviously gained much traction after the September 11th attacks. The establishment attitude to Muslim communities in its midst varied from country to country, but at least in the British and American context officialdom's political and security discourse differentiated between 'good' (moderate) and 'bad' (extremist) Muslims. The latter were positioned as utterly unusual because of their uncompromising religious/political positioning, desire to afflict mass civilian casualties, and utter disregard for their own lives in the commission of terrorist operations.
Moving specifically to IS, for adherents their "caliphate" is the only place it's possible to live properly Islamic lives. In their cod theology, they see themselves as a state actor setting about the work of constructing something new that could attract Muslims from all over. Therefore it and its co-thinkers in Boko Haram have temporal and territorial aims. They want to create a space that removes uncertainty and indeterminacy and forces Muslims to choose between the land of belief and the lands of unbelief. They also look toward eternity in the belief this brings on the end times: in sharpening the confrontation between IS and the West via terror attacks, the more that is being done to bring on the final battle and the coming of the Kingdom of God.
For Paul, the problem the West has is all military action does is feed their theology. Long-term, particularly here, there has to be the creation of alternative religious narratives that prioritise negotiations between Muslims and other faiths, while all the time challenging the apocalypticism underpinning IS and other species of Islamism. For example, the present bete noire of the Turkish government, Fethullah Gülen argues that rather than opposing a liberal Islam to their fundamentalism, one needs to centre on the critical resources within the belief system and articulate an agenda of critical questioning. IS justify their atrocities according to convenient scriptural authorities, but at the same time it may contain the seeds of their demise.