Yeah, Christian government works so well. Massachusetts had it for centuries, had an Established Church until 1833, even had blue laws up until recently, and look what an ornament to virtue it is today. For that matter, look at what an ornament it was fifty years ago.
Christian government works fine as long as it is done voluntarily and without an extreme legalism (obviously it would have stricter laws etc. though than we have today). I would love to live in a little town or something in which everybody covenants together as a Christian society provided this was the case.
What happened with Massachusetts is that people lost that vision, which led to stricter laws in an attempt by the leadership to hold on to their dream (and once sin crept into it, their power). At that point, more people turned away, and the situation was out of control. It was no longer a society that should have been Christian in terms of laws etc. since they were not covenanted together for the purpose.
Yet, they tried to keep a facade of such for centuries after 1700. That probably made their problem worse.