Is the ingenuity of our judges and lawyers so trifling we cannot establish that linkage without revealing things that are truly secret? (Establish waterboarding, for instance, without going into what questions the torturers were asking? Or conduct certain proceedings in camera?) Is it beyond all possibility to chart a judicial path to consequences for the people who did these things?
So: We now know that fundamentally the OLC is coloring outside the lines, making up presidential authority where none yet exists. If we were to proceed lawfully, we would need a constitutionally-sound, explicit and bona fide Congressional authorization.
The internal justification for area bombing either espoused a view that civilians were collateral damage to attacks on the industrial war machine or that in modern warfare, the civilian/combatant distinction was not viable or important. In some cases, bombing of civilians was, ironically, presented as humanitarian and in keeping with the larger goals of the law of war, in that collapse of the enemy could be precipitated faster, and at a lower cost in human life overall, if civilian morale could be broken from the skies.