Beliefs alone do not curtail behavior; hence your next sentence mentions enforcement. To repeat my example, I may believe eating meat is unethical. This alone would not curtail anyone's behavior. I might advocate for some kind of enforcement, or I might try to peacefully persuade people that my position is correct, or I might quietly fret and wish the world were a better place. It seems to me that you are assuming that people who oppose these behaviors must necessarily approve of exercising government power to dissuade or prevent people from the behaviors. It is hard to have a discussion when you get to define the terms. Don't some pro-life people condone abortion when the life of the mother is in jeopardy? I think I understand your big idea, and I don't discount your concerns about a slippery slope. I just find your language very absolute and self-righteous, the same characteristics that make it hard to discuss ideas with a religious ideologue. ("You cannot be evangelical and pro-life and support limited government" -- when, again, enforcement of morals would be a very small slice of government activity, and doesn't everyone support a limited government to some extent?)If you are Evangelical and Pro-Life, you subscribe to two sets of beliefs that strictly curtail the behaviors of other people.
I think you are reading things into my statement that aren't there. There are Christians ike yourself, and of several different types, that believe in Christianity and practice it in their way. Evangelical Christians are a specific subset that PUSH the beliefs onto other people. Imposing the belief system upon everyone is the definition of evangelical. You are one of the more moderate Christian flavors that does not champion the imposition of Christianity upon all people. I'm simply saying that a government based upon the idea of forcing all residents into a specific belief system is going to require an enormous security/surveillance apparatus to measure people's adherence to these beliefs. Therefore it is cognitively dissonant (or willfully ignorant) to believe that evangelism is compatible with the goal of "small government".