Central to any discussion of whether or not theonomy is confessional (at least with regard to the WCF) is WCF 19.4. Here is what that section says:
To them (Israel, LK) also, as a body politic, He gave sundry judicial laws, which expired together with the State of that people; not obliging any other now, further than the general equity thereof may require.
One must first ask the question of what “general equity” means. Whatever it means, it cannot refer to the entirety of the judicial laws. Otherwise, nothing “expired” whatsoever. Also senseless would be the statement “not obliging any other now” if general equity meant the whole of the judicial law. The impression that is given here is that general equity is considerably smaller than the judicial law. To say that general equity equals the entirety of the judicial law makes mince-meat of this section of the WCF.
So, if is not equal to the judicial law, then what does the phrase mean? We must look to context to see what that means. It is helpful here to see that the WCF regards Israel as the church under age (19.3). Now, let me be clear. I think that modern governments should rule justly, and in defining what is just, I use the Ten Commandments. It seems to me that many theonomists give us two choices: either be autonomous from God and have a civil government that has no relation to the law of God; or, conversely, have a theonomic government that governs according to all the judicial laws of the Old Testament. However, is there not a third option? Can not a government rule according to the Ten Commandments, but not according to all the Old Testament judicial regulations? That would not be autonomy, since it is based on God’s law, not man’s. At the point of law and determining what is just, I have more than a little sympathy for what theonomy has to say. Are we choosing man’s law or God’s? Which one is righteous? To ask the question is to answer it. However, the Ten Commandments simply do not apply the same way in the New Testament in all circumstances as they did in the Old Testament. And here is where I differ with theonomists, and this is where I feel they caricature the non-theonomic position most badly. There is no room in most theonomic minds for a government that rules according to the Ten Commandments, but not according to the Israel-specific judicial law. That is not even a possibility. I have yet to see a theonomic reckoning with this position. Therefore I interpret the term “general equity” to mean what comports with the Ten Commandments in a non-Israelite setting. Indeed, one could also equate the term “general equity” with the second use of the law, which is to restrain evil in the world. I do not feel that theonomic positions have interpreted WCF 19.4 correctly.