The wheels grind slowly here. Mostly they grind fairly small.... my record for a delayed response to an e-mail was 2 1/2 years, but I got there.
But I do owe David M who posted a comment on an earlier post an apology, because it's sat in my inbox far too long. Here we go:
The question that I'm left with is: what's the Biblical basis for your view of the role of government? (By which I'm not trying to imply that I don't think there is one!)
Romans 13 has to be a key passage. One key principle is surely this one: "For there is no authority but from God" (v1). That means that government is a "positive" institution: the authority is a positive grant from God.
It follows from that that the question then becomes, "what authority has God granted to governments?" Because any other "authority" then seek to wield cannot be legitimate. When Peter said, "We must obey God rather than men", he showed that this authority grant was not unlimited.
Then the question has to become "what authority has God said in the Bible as being granted to governments?" Because it is inconceivable that God has given such important authority without telling us what it is, and the Bible is where God reveals his mind. How can he be a "servant of God" (v4) unless God gives him some instructions for his service?
Verses 3 and 4 also make clear the positive and negative side of the government's work. Positively, to reward what is good; negatively, to punish wrongdoing (and thereby cause fear in others to prevent them from doing it).
Of course, "good" and "evil" must also be defined by Scripture. The government should not arbitrarily decide, for example, that earning an un-approved of amount of money is an evil to be punitively taxed, or that sexual perversions are a good that needs lots of funding to promote and protect.
Also, it does not mean that
all good and
all evil are within the realm of government. Nobody should be imprisoned for original sin or unbelief, and the government should not break down your front door to make sure it rewards all the acts of kindness between brothers and sisters in the home or reduces taxes for believers. I believe in the idea of "sphere sovereignty" - God has instituted different authorities, family, church and state, and these are not a neat hierarchy with state at the top, but overlapping spheres.
The Old Covenant law can guide us, if we make due allowance for its unique nature as the Covenant between God and his theocratic nation. This is what the Reformers meant by the "general equity" of the law - it has useful and abiding principles. It is wrong to retain the theocratic clothing, but the principles remain.
One important thing is that there is no hint that the government's authority depends on the mode by which it gained power. If someone seizes the role in a sinful way, yet they still in fact hold the role (and will be accountable for what they do in it) - and holding the role is the bit that makes them have the authority, not the manner of gaining it. This is implicit in Romans 13:1, given the Roman government of the time - which gave Paul privileges we can see in Acts (e.g. Acts 25:11).
There's so much more to say. I think I should leave it to any commenters to decide where we want to go next. But essentially we are saying that the government's mandate is moral. Their laws are to be related meaningfully to the summary of the Mosaic Law, "love your neighbour as yourself" - though in our present context (evaluated Biblically), not that of Moses. They are not to be arbitrary impositions for other ends. This is the Biblical grant to governments.
In practice this looks/sounds something like: adultery is a terrible/wicked/immoral thing, but it isn't the job of the government to issue laws against it. Correct me if I'm wrong, but I think this is roughly where you land too.
In the past I would have agreed on this particular example, but now I don't. I do not think that the present UK government should have such a law, because ultimately (the big picture of Scripture shows us), law can only really be fulfilled on the foundation of free grace - the grace of the gospel. Without the gospel foundation, we cannot workably have proper law. (That sounds like pragmatism, but I think it is Biblical pragmatism based on the big picture of Scripture). But, in a society where the gospel had worked its leaven-like ways, I do think that adultery should be a crime, as indeed it was in the UK. Why? Because marriage is a public covenant, not a private one. Married households are intended to be the units of a godly society - they are not secret, hidden entities. Acts that directly attack that basis should be crimes.
But if we chose a different example, I could well agree. Being deliberately nasty to people is wrong, but should not be a crime if it falls short of violence, harassment or an incitement to violence. Not keeping your promises is wrong, but should not be a crime if it falls short of a contract or if no significant loss is sustained. Of course, there is work to do in deciding where the boundary lies, but you get the point.
The basic idea of theonomy, as I understand it, is that the civil/judicial parts of the Mosaic Law (according to the tripartite division a la Aquinas and Calvin) teach us what God expects from a government - which would extend its role beyond your view. (This is probably a naive/simplistic explanation, but hopefully not inaccurate.)
I suppose this depends on in what manner they "teach us" - what filters and lenses there are to be applied between the Mosaic context and ours. I think what I wrote above would be accepted under the label "theonomy", given that I said that all law should be justified meaningfully from Scripture. But the label seems to be used quite widely, and I am not very competent to answer a lot of questions because I need to do more of my own study...