It is a gross abuse of language to identify area bombing as a "war crime," as do some modern critics. The policy was designed to hasten the defeat of Germany by destroying its industrial base, not wantonly to slaughter innocents. Yet it remains a blot on the Allied conduct of the war that city attacks were allowed to continue into 1945, when huge forces of aircraft employed sophisticated technology against negligible defences, and German industrial output could no longer much influence outcomes. Both the operational necessity to attack cities -- because the RAF was capable of nothing else -- and the strategic purpose of such operations were gone.It's a fairly general principle that the laws of war require that violence be necessary and proportional, and by Hastings's own account, at least the 1945 city attacks (Dresden, Potsdam) were neither.
Hastings also omits to remember that just a page or two earlier, he had written:
[Churchill] also gave a formidable hostage to history, by declaring that Bomber Command's campaign was terroristic. No one in the upper reaches of Britain's war machine had ever privately doubted that this was so, but ministers and airmen took elaborate pains to avoid acknowledging it.So much for "designed to hasten the defeat of Germany by destroying its industrial base"; as Hastings well knows, area bombing was adopted precisely *because* bomber attacks could not focus on the "industrial base."
(Leaving aside that Britain built Bomber Command, even before the war, with the intent to conduct terror bombing, as I learned in reading Bomber Command by Max Hastings.)