The relationship between religion and politics is a bone of political contention and a source of deep confusion across the Islam-West divide. When most Western liberals cast their gaze on Muslim societies today, what they see is deeply disconcerting. From their perspective there is simply too much religion in public life in the Arab-Islamic world, which raises serious questions for them about the prospects for democracy in this part of the world. This article examines the relationship between religion and political legitimacy in the context of the contemporary Muslim Middle East. Specifically, it seeks to provide a broad historical answer to the question: why at the start of the 21st century is religion a powerful source of political legitimacy in Muslim societies while in the West, by and large today, it is a source of disagreement and hence illegitimacy?