I think you are being a little more than a little cagey in your angling here to condemn torture outright. You say you are trying to narrow down what Paul means by endorsing the Roman “ministry of the sword”, but I think you’re simply trying to avoid the question of what is actually permissible.
I have already given you (once for sure; maybe twice) exactly what Paul means by saying what he said in Rom 13. Paul is endorsing the function of government which uses force to oppose those who cannot abide the prescriptions of law. If you want a finer-grain detail than that, I’ll add this: there is no question in my mind (and I hope not in yours either) that Paul’s view of justice is almost wholly-informed by the Mosaic law, which provides the death penalty often as the punishment for crime; insofar as the Roman law mirrors the Mosaic law, Paul would find it both right and just. If you don’t understand how I reach that conclusion, please re-read Rom 1-2 to see that Paul would say plainly that the Gentile who has never had the Mosaic law must indeed see the moral decrees of God in creation because he (the gentile) abides by them from time to time. This has to include those who judge others as Paul covers them in Rom 2 specifically.
In that arena for this discussion, your grasping at the atrocious to disqualify the obvious is uncalled-for. If we harmonize Rom 1-2 and Rom 13, we get a very easy-to-grasp view of what Paul means: government is, by virtue of its God-ordained role in the world, responsible to use violent means to deter and also to punish men who do not abide by the law.
Are there boundaries for that responsibility? Sure there are — not the least of which are the presuppositions of actual justice and actual relative offense. This is absolutely indicated by the Mosaic law as someone needs to be actually convicted of a crime before a penalty can be leveled against him — even for as little as a slap in the face against him. It is also indicated that death is not the only prescribed punishment in the Mosaic law — restitution and restoration to the offended also is demonstrated heavily, so there’s a scale of offense and a scale of punishment.
You know: if the mayor of your town set forth the principle that in every day that a crime is committed in Reynoldsville he will put one random person to death, that would certainly be a use of violence to deter crime — but there’s no justice in it. On the other hand, if the same mayor started putting people to death for speeding, there’d be no measure of the relative offense — the punishment does not fit the crime.
Your view simply overlooks this entirely — it comes out under the cover of words like “civilized” (as if that’s what it means to be “Christian”), and doesn’t make fair enough distinctions about justice and scope of offense to apply to any matter in particular.
But you keep resorting to the egregious to make your point. Even if all of them are valid examples of things we should not do, this doesn’t drive us to any biblical or principled understanding of the matter. At some point, there ought to be (there actually are) boundary markers to grasp what is at stake here, and how to act if you find yourself to be a Christian who is also the 5-Star General in charge of the Army or the Director of the CIA — or perhaps only the sergeant or agent who has an enemy combatant in custody.
Your discussion so far doesn’t help any of those people. You want to point out that we shouldn’t boil anyone in oil. Really? Why? “Well, imago dei, obviously,” but that’s not half as reasonable or obvious as you should think.
What I could do is line out all the things the Judges did to the enemies of Israel in the book of Judges, and what David did to those opposed to God and Israel, and then run through a handful of punishments the law of Moses defines as totally just when handed down in Israel. But rather, I want to turn to the Gospel of Jesus for a moment to point out something far more obvious than the response that boiling in oil is an atrocity.
The punishment Jesus received is the punishment we deserve, judicially. This is an unequivocal truth of the New Testament. So while we may want to call boiling in oil or running people into hungry wild beasts things the Romans did unjustly and without warrant, the Gospel Paul preaches tells us without any question that the just punishment we deserve as sinners looks like what Jesus received at the hands of the Jews and the Romans — a bloody beating, a public humiliation, a painful suffering, and death.
You cannot deny that Paul says that this is the punishment we deserve. And in that, in some sense Paul is saying this terrible fact of the punishment we deserve ought to change our minds. The rightly-just threat of punishment ought to have some psychological or emotional effect on us.
In that, Paul frames a theory of just punishment which is at odds with your view — but is manifest in Rom 13 where he says that we should not fear the government if we do good rather than evil.
What Paul endorses, you have plainly denied. And this is just about common civil order at this point — not about a theory of war and conducting a right act of violence against a nation or an army which has come to invade or plunder or simply to terrify and exploit.
The question of whether torture is permissible or even tenable for the Christian magistrate or military officer starts with the correct picture of justice — what is the right-sized punishment for a crime? To what lengths can the modes of punishment — including right-minded views of restitution and avenging a past crime — be employed under the umbrella of “justice”? You have not approached these questions at all, and your right-hearted fear of acting without grace or mercy has overcome what should be your right-minded belief (and fear) of God’s holiness and wrath as it ought to be exemplified in the acts of the government.
While I think you are at best failing to show some of your moral calculus here, at worst you may be missing the point of the Bible itself by missing the key matter of the scope and force of justice in God’s economy. There’s much more to be said here, but I look forward to your response to this.