Separation of Church and State

Secularism is often associated with the Age of Enlightenment in Europe, and plays a major role in Western society.
It facilitated a huge growth in wealth.

Marxism and events such as the Great Purge, the Chinese Cultural Revolution, and the actions of the Khmer Rouge are an attempt to kill off the Church part.
Sharia law simply seeks to reverse the separation - one religion, combining church & state and whack a huge veil over the internet