Green Baggins has been having a prolonged debate over the “Escondido” model of statecraft. Unfortunately, it’s difficult to have a real debate in that venue because Reed DePace gets his pink tutu in a knot when things are going badly for his own team. So I’ll just make a few broad observations here:
1. A Theocratic State
i) Israel was a theocratic state. The classic Anabaptist argument against any carryover of the Mosaic law into the new covenant seizes the theocratic dimension of ancient Israel.
And that’s an argument which has the strengths and weaknesses of a half-truth. It’s true that there were some unique aspects to the status of ancient Israel. Laws which prefigure the Messianic age. The cultic holiness of the land, the people, the Temple, &c.
So there’s undoubtedly a fair measure of discontinuity between ancient Israel and the church, or the old covenant and the new.
However, that analysis is very lop-sided. Not only was ancient Israel a theocracy, it was also a nation-state. Stop and ask yourself what the Mosaic law would look like if Israel were only a nation state, and not a theocracy. What would be absent? What would remain?
It would still have laws on sex crimes, property crimes, crimes of violence, and so forth. So it’s simplistic to relegate the whole Mosaic law code to the era of types and shadows. That’s a catchy slogan, but it overlooks the obvious.
ii) Keep in mind, too, that the Mosaic law is the only inspired law code we have. So there’s an obvious value in using that as a frame of reference rather than merely human law codes.
iii) A more principled, potential objection to the relevance of the Mosaic law is that many of its regulations are quite timebound because they are adapted to the socioeconomic conditions of life in the ANE.
At the same time, many Mosaic regulations may also exemplify generic principles which can be abstracted from the specifics of the historical setting.
Indeed, we do the same thing in reference to NT ethics. We need to distinguish general norms from timebound applications. We also need to analogize from the situation of 1C Christians to the situation of modern-day Christians.
So the more responsible course of action would be to evaluate OT laws on a case-by-case basis. There’s no antecedent presumption one way or another regarding their contemporary relevance. We only know by looking inside the box and sorting the contents.
2. The Decalogue
The Confessional tradition of the Westminster Standards codifies the continuing relevance of the Ten Commandments. That, however, carries certain implications:
i) The Ten Commandments can't be confined to personal ethics. They weren't merely, or even primarily, a rule for sanctification. In context, they concern social ethics. Public policy. To restrict them to personal ethics flouts the original intent of the Decalogue.
ii) The Ten Commandments can’t be put in airtight compartments which isolate the Decalogue from the subsequent case-laws. For the Ten Commandments are just a set of general norms, while the case-laws illustrate specific ways in which the Ten Commandments apply to particular situations. Put another way, the case-laws function as a commentary on the Ten Commandments. How the Ten Commandments were understood to apply at a concrete, practical level. A detailed explication of the Ten Commandments.
Therefore, to the extent that Confessional Presbyterianism is committed to the contemporary relevance of the Decalogue, it is logically committed to case-laws insofar as they unpack the Decalogue. That’s a corollary commitment.
Of course, that’s still subject to the caveats under (1-iii).
3. Klinean Statecraft
Although some Reformed Presbyterians talk like Anabaptists, a more popular move in Reformed circles is to go the Klinean route, with intrusion ethics, a secularized redefinition of common grace, &c. The leading exponent of this position is Lee Irons.
Debates over 2-k can be very theoretical. But it’s useful to bring this down to earth. Lee’s support for “civil” sodomite marriage is a good test-case of what Klinean statecraft means in real-world terms. And you can take it from there.