Brief article by Shadi Hamid on why Islam cannot be secularized.
Islam, in both theory and practice, is “exceptional” in how it relates to politics. Because of its outsize role in law and governance, Islam has been—and will continue to be—resistant to secularization...Two factors worth emphasizing: First, the “founding moment” of Islam looms large. Unlike Jesus Christ, the Prophet Muhammad was a theologian, a preacher, a warrior and a politician, all at once. He was also the leader and builder of a new state, capturing, holding and governing new territory. Religious and political functions, at least for the believer, were no accident. They were meant to be intertwined in the leadership of one man.Second, more than merely the word of God, for Muslims, the Quran is God’s direct and literal speech. It is difficult to overstate the centrality of divine authorship. This does not mean Muslims are literalists; most are not. But it does mean the text cannot easily be dismissed as irrelevant.///
http://www.brookings.edu/research/opinions/2016/06/03-islam-different-from-other-religions-hamid#.V1V_uK2ADnd.facebookHe could have also mentioned the concept of Biddah which explicitly prohibits any change in the religion.