It has been argued by the proponents of political Islam that state and religion (din ve devlet) are inseparable in Islam, short of a state that operates within the bounds of ?eriat (Shari'a) law and / or that is run by the Caliph of the Muslims, it fails to be accepted as legitimate. Similarly, with the recent revival of political Islam in Turkey, the secularists have come to expect that demands for the re-institution of the Shari'a rule and the Caliphate are imminent. Meanwhile Mardin, Gile, Toprak and others have argued that democratization and capitalism have been altering the lifestyles of revivalist Muslims in Turkey and rendering the efforts at promoting Shari'a law and Caliphate obsolete. This paper sets out first to establish the extent, nature and changes in the popular support for Shari'a rule and the re-institution of the Caliphate in Turkey. Secondly, it seeks to inquire into whether political Islam lead to increasing demands for Shari'a rule and erodes democratization in Turkey. Using nationally representative surveys conducted by the ISSP in Turkey in 2009, this paper seeks to examine the relationships between religiosity, democracy, and the demands for Shari'a rule and re-institution of the Caliphate in Turkey. The first part of the paper consists of the theoretical analyses of the relationship between religiosity and democracy, on the one hand, and democracy and the demand for Shari'a rule and re-institution of the Caliphate, on the other. The second part of the paper utilizes findings of several surveys compiled in Turkey to assess how popular orientations toward Shari'a rule and political Islam changed since the end of the Cold War in the country. Finally the last part of the paper comprises of the empirical analyses of the hypothesized relations between religiosity, democracy, attitudes toward the Shari'a rule and the Caliphate.