Just in case the past two thousand years have provided insufficient warnings as to what happens when religion takes over, or you really buy the "but we're different! Those guys got it wrong by torturing, brutalizing and killing everyone who disagreed; we still love the sin even though we hate the sinner!" (which is a load of crap if ever there's been one), here's a modern day example of evangelical Christianity sans separation of church and state.
The road to hell is paved with good intentions. The smiling, polite preachers and missionaries who spread their doctrines (and, mostly, escaped before the consequences were realized) are directly responsible for the hell they've unleashed on these innocents.
And I'm sure most of them happily cite, in the unending Piety Games of evangelism, their exploits of "spreading Jesus' love" and "saving souls", and imagine themselves victorious warriors in a supernatural war. All without giving a second thought to what they've actually done. And the worst part? They'll be inspiration to their church groups and peers, to do the same harm here and elsewhere. I remember the various churches I've attended doing this same thing, at VBS', in lieu of or following sermons. Ugh.