If the State does allow the church to maintain some sort of sanctioned police force, it'll pretty much need to be limited to the school parts and have very narrow and well defined powers, much like the jails at Philadelphia Eagles stadium.
I'm just wondering why they can't have the state post some units up in that area permanently and the church can hire some private security. There really is no need to give them their own police force. Also, as I understand it, this isn't purely about a school, so I'm not sure its as applicable to other university situations as others have pointed out.