A great question facing Islam–and for us as we face Islam–is whether there are authentically Islamic sources that can religiously legitimate democracy and religious pluralism.
From the beginning, Christianity has had the great asset of what some derisively call its “dualism” – the conceptual resource for distinguishing between spiritual and temporal authority, which has given it enormous flexibility in relating to different political and cultural circumstances from Theodosius to Hildebrand to the religion clause of the U.S. Constitution. Islam is emphatically monistic. That is a great asset when joined to military and political power in the course of conquest, but a disabling weakness under the conditions of postmodernity.
The rest here.