Chugalug,
Yes indeed, Law Of Armed Conflict is what I meant. The basic building blocks of which are Necessity, Humanity, Proportion and Distinction.
One must make the distinction between military and civil targets, one mustn't use inhuman methods to kill (killing in itself is fine), one must be proportional and attack sensible targets, not wipe a race off the planet when only a few would do. One must only attack those things that are actually necessary to achieve the aim.
Now, this is of course modern thinking. I have no idea what the guys were briefed at the time, or what the law was. I only offer the above as that is what I was briefed and what I adhered to when it was my turn to employ HE on Her Majesty's foes.
I cannot speak for the RAF as I am not a part of it, but in my opinion, when measured against this contemporary yardstick, the combined RAF/ USAAF bombing campaign falls short on three out of four counts. That would, in my opinion and in today's environment, make the campaign a war crime, pure and simple. I still support what they did. They didn't do it today, they did it in a time of incredible evil and absolute necessity.
I honestly believe the problem has always been one of honesty. Attacking civilians because you can't accurately target anything more meaningful, or targeting civilians knowingly as part of taking on a target set within a city is, quite simply, attacking civilians. We shouldn't try to skirt the issue with handy catch alls like 'Total War'. We should be bold enough to commemorate and appreciate what the boys did, because in the (fairly exceptional) circumstances, they did the right thing.
PN,
Yes I do get your point and you make it well. I think my personal distinction is that using a HE warhead to kill people with blast and fragmentation is a different proposition to deliberately using HE/ incendiaries to start a firestorm. Just my opinion.