Over the past few months, certain writers and columnists have been discussing a phenomenon called "Christianism." Andrew Sullivan says "Christianism is an ideology, politics, an ism. The distinction between Christian and Christianist echoes the distinction we make between Muslim and Islamist. Muslims are those who follow Islam. Islamists are those who want to wield Islam as a political force and conflate state and mosque."
But some would prefer a term other than Christianist: "Christianists...seek to apply their own narrow interpretation of God's law to society at large, punishing those who disagree, and emphasizing adherence to rules over grace and mercy. They might even invent new laws based on their understanding of scripture. Folks like that were called Pharisees back in Jesus' time. Maybe it's just as good a name for them today."