The word Christianism is being used as a descriptive term for Christian political conservatives mostly in the United States, for the ideology of the Christian Right, meant as a counterpoint to "Islamism". Writing in 2005, the New York Times language columnist William Safire attributed the term (in this novel usage) to blogger Andrew Sullivan, who wrote on June 1, 2003, page 19, "I have a new term for those on the fringes of the religious right who have used the Gospels to perpetuate their own aspirations for power, control and oppression: Christianists. They are as anathema to true Christians as the Islamists are to true Islam." The bloggers Tristero and David Neiwert used the term shortly after. Sullivan later expanded on his usage of the term in a Time magazine column. Uses of the term can be found dating back to the seventeenth century, but these are unrelated to its modern meaning.
This meaning of Christianism has started to gain a foothold in the United Kingdom too, according to one commentator.
This Americanism circumvents the etymology of the suffix "-ism" which means "doctrine, theory, system of principles" (the other meanings are not applicable to religions) whereas the suffix "-ity" means just "state, quality or condition". In other Latin-based languages such as Castilian,Galician and Catalan and from other countries such as Portuguese, French, Occitan, Italian, etc. the suffix "-ity" (-idad, -dade, -té, -ità) means Christians as a group, their geographical distribution, and their shared cultural identity, what in English is called Christendom, with its own suffix being of Germanic etymological roots.