When the king becomes a Christian and asks "does the Bible say how I should rule my people" – I don’t think an appropriate answer would be that Jesus doesn’t talk about that, he’s unconcerned.
Thanks Tyler, and yes, I’ve put quite a bit of effort into this very issue. See here for instance!
The above is the fruit of a friend’s and my labors 5 years ago recording an audio book version of the first book of a trilogy that addresses “What if the civil magistrate feared God? What should he be taught? What should he do?”
It’s exactly someone like me (and you) who needs Ellul’s exhortation.