It seems to me that much of modern Presbyterianism shares (unintentionally to be sure) significant parts of a Roman Catholic definition of the Church. The Presbytery is considered a church, and the minister is not a member of his local congregation. Furthermore, they forbid lay baptisms, and some even argue for an apostolic succession of elders.
This same problem is seen clearly in discussions on politics, as well as discussions on “the Spirituality of the Church.” The Christian Reconstructionists, who thought they were “integrating” the spheres of Church and State, still bought into the basic presuppositions of the problem: that “Church” equals Visible Church stuff and that “State” equals something that begins outside of Church in need of influence by Church. Thus their Christian state left us with a monarch, president, or voting committee who was subservient to the ministers. The other side of the coin, the neo-Two Kingdoms doctrine, coming out of California (where nothing good ever comes! jk 😉 ), also fails, as it buys into the theory that there is even such a thing as a non-religious secular and that this thing is essentially just peachy. God, according to their view, is really only concerned with the visible church on Sunday morning.
What we need in order to avoid both pitfalls is to be able to preserve a notion of secular space, as in civil and “natural” or “created order,” while at the same time insisting that it is not in the least existing independently of God’s grace. This doesn’t mean that the secular is dominated by the sacred, nor even by our notions of Church stuff. Indeed a good old fashioned doctrine of “the priesthood of all believers,” vocation and all, should help us along the way. In other words, our own Protestant history is our best friend.
Paul Avis explains the Reformer’s position like this:
It is essential not to think anachronistically of the Church’s dependence on the magisterial structure of society in the sixteenth century. For one thing, the Reformers are not adumbrating a theory of the state at all (least of all, of the modern secular state): theirs is a view of society, not of the state; of Church government, not of political theory. The background is the theocratic corpus Christianum of the medieval synthesis of Church and commonwealth. The theory of the godly prince was not what it may appear to us to have been– an appeal from Chruch to state in what was essentially a religious matter. It was an appeal from one officer to another within a single society, the Christian commonwealth.
~ The Church in the Theology of the Reformers pg. 132
Avis goes on to explain:
For the Reformers, these represented two aspects of one social entity. In no school of sixteenth-century thought- except for some varieties of anabaptism- were Church and commonwealth actually opposed: they were distinguished but not divided.
The Reformers could say that the King was a legitimate minister of God, because they did not believe in a special priestly caste and because they believed in common grace, or perhaps better, they believed in the continuing integrity of creation. The King was a true minister and if a believer, a true priest because of the universal priesthood of all believers.
In the case of a Christian King, the society simply had a believer-priest in a position of great practical benefit. He could make sure that order was carried out. In the case of someone like King James, he could also make sure that the professional theologians were kept tethered to the real world, where certain particular debates should take the back seat for the good of the country, which would then also be for the good of the Church.
We could summarize the distinction of duties by saying that the state protected the true religion and the Church distributed that religion.
To understand the Reformation you have to understand the godly prince.