State religion is indeed a heresy, a Gnostic heresy specifically. My alter-ego just finished the introduction to gnosticism (note the differences in capitalisation, there is a reason for that) earlier today, which also ties in with modern secular ideologies (e.g. Marxism). It's gnosticism all the way down, and it's spooky in the way it bastardises both faith and reason.
RE: A Deeper Separation of Church and State