Qualifications. Barring the future advent of antimatter, black-hole, or similar weaponry, nuclear weapons are the standard-bearer for destruction in our world.
Their comparison with chemical explosives is typically mediated by an estimated TNT equivalence; but so it turns out that there is an incredible range of comparison available, with fission bombs tending towards an equivalence of tens of thousands of tons of TNT on the low end, and almost a million tons on the higher side; and then fusion bombs can be scaled up arbitrarily, although impractically, hovering in the "millions/tens of millions" range as far as actual (tested/on-hand) samples go.
The point is, a Hiroshima-sized blast in a major American city would presumably cause much less death/damage than a Castle Bravo kind of blast; and so talk of "continental nuclear war" is ambiguous between, say, the use of Hiroshima-scale bombs on a large number of cities, and the use of Tsar-scale bombs on the same. For the purposes of this question, we will frame the local comparison in terms of either range of scales, with specific qualifications justifying the description "physical near-equivalent to continental nuclear war" as such.
Question. Imagine that there was a war during which at least one major faction used approximately 10,000,000 tons of aerial bombardment and artillery, including several hundred thousand tons of napalm; and all this alongside an extensive quantity of mutagenic chemicals and an undetermined number of grenades (so suppose further that there was at least one year in which this faction's military placed an order for, say, 379,000,000 incendiary grenades, notwithstanding that this order was perhaps not met in that single year, neither was there ever a year in which so many grenades of any kind were used).
This would be analogous to five hundred Hiroshima-level bombs, or ten typical fusion bombs. Perhaps few major cities were significantly damaged or destroyed; perhaps the majority of the expenditure was directed at suburban/rural areas. In any event, suppose that as many as 2,000,000 civilians died in the one nation subjected to all this firepower. (It is possible that several other nations were also devastated, on account of significant levels of aerial bombardment, by the same faction; but we will suppose that only one nation, in this theater of war, was subjected to the full array of relevant ordnance.)
Allow that the mutagenic chemicals that were used resulted in hundreds of thousands of direct casualties (deaths and debilitation) and, after the war, hundreds of thousands of deformed stillbirths, etc.
By virtue of the quantity of explosive force unleashed, and the mutagenic residue left in its wake, here, does this consist in a physical near-equivalent to continental nuclear war, and if so, do whatever moral standards apply to genuinely nuclear war, apply in this case, if not one-to-one, at least to the extent required to judge the culpable faction as guilty of whatever wrongdoing we would attribute to executors of genuine nuclear war?
Or are the internal physical differentiae between the case types enough so as to commend a less drastic moral evaluation of the offending faction?
Reasons against a congruent evaluation: the process of inflicting subnuclear destruction on this scale would, barring an incredibly large air force/artillery array, take far longer than inflicting nuclear destruction on the same scale. Moreover, then, such a war would pose less of an escalation risk than first-use of even a single fission bomb would. Per Kant/Rawls, that a major global power (likely the only class of military power capable of marshalling the resources for such expenditures) would do such a thing to a much weaker nation (one with next to no chance of retaliation against the offending military's homeland) would exemplify that contempt for humanity (or even physical reality itself) which might increase the risks of nuclear first-use situations down the road; but that is a very slippery slope that our minds (not often programmed for suicide) nevertheless wear some very spiky shoes while inclined upon.
The piecemeal nature of the subnuclear discharges would also tend to churn up less particulates than a mass nuclear strike would, so the impact on the ambient global climate would seemingly tend to be less in the subnuclear case. (I'm not 100% about that, to be fair: there was, after all, a real war pretty much just like the imaginary one described here, and I don't recall whether climate dynamics were aggravated by the real example, though I have a hazy memory that they might have been.)
