"[G]et government out of the church. If that were the case then the government would only oversee the civil contract between two people." This poses some real practical issues, such that it seems that there may be no way to get from here to there. Cases:
1) Two Catholic wed and agree, civilly, that a Church Tribunal shall have the last word on the validity of their marriage. They also agree in their pre-nup contract that, if either of them runs off, the other party shall have custody of the children and all the family property. One of them subsequently runs off without getting a canonical annulment. A squabble over the kids and property follows. How should a government court rule?