A recent Commonweal issue included a review of a book entitled The Fire-- The Bombing of Germany, 1940-1945 by Jorg Friedrich. The reviewer was James Sheehan. The book describes the bombing of civilian targets as a key battle tactic by the UK and the US during the second world war. The idea was to break the morale and destroy the productive capacity of the Germans. All in all, about 600,000 Germans were killed, and three and a half million homes were destroyed. Friedrich's book, in the words of Sheehan "seeks to convey the horror of the bombing with examples, a litany of relentless suffering that describes the air war's impact".
Sheehan tries to make a moral argument in favor of this tactic, and I believe he falls flat on his face. Noting that this strategy contributed to the allied victory, he asserts that there was no alternative. Otherwise, the Germans could have prolonged the war, leading to more civilian deaths in the long run, and leaving the Nazis free to further their murderous campaign. Sheehan argues as follows: "Assessing the morality of the bombing requires us to weigh the consequences of the alternatives, and to ask whether the means used were proportionate to the good that was sought." He goes on: "For the practitioners of war, the problem of ends and means is especially difficult because in war the means are always evil: violence is never contained, innocent blood is always shed." Hence, he concludes, the bombing was a necessary evil.
But evil is never "necessary". Sheehan makes the same mistake made by those who defended the actions at Hiroshima and Nagasaki, and who give the nod to torture today: they fail to recognize that some acts are intrinsically evil, evil in their very object, and can never be defended by appeal to intent or consequence. And the prohibition in the natural law against killing innocent human life is absolute. Instead, Sheehan embraces proportionalism, the notion that assessing morality is simply a matter of weighing the different options, and choosing the best of the alternatives. He embraces consequentialism in that the "end" of defeating Germany quickly justifies the "means" of fire-bombing cities.
Sheehan would do well to review the classic double effect principle, now being debated at Vox Nova (here and here). For, as we know, proportional calculations do indeed play a role in the calculus, but only if we pass two hurdles first: that the act itself is not objectively evil, and that the person making the choice does not share the intent of any evil side effects. If the act is intrinsically evil, it cannot be justified by using a proportionate reason to do it, or as a proportionate response to some circumstance. In the current case, we do not even get past square 1. Deliberately attacking civilians can never be justified, period. Pope John Paul devoted his greatest encyclical, Veritatis Splendour, to exactly this issue. He says it quite clearly: "circumstances or intentions can never transform an act intrinsically evil by virtue of its object into an act subjectively good or defensible as a choice."
Of course, assuming that the second world war met the just war criteria, then simply fighting the Germans would not in itself be an evil act. This is a crucial distinction that Sheehan sweeps over when he claims that the means are always evil in war. So, when assessing civilian deaths in war, proportional calculations come into play if the protagonist does not target them directly. But even here, there is a tendency to be overly-lax in the application of proportionality to real world considerations. Simply not willing the deaths of civilians is not enough. A too-ready acceptance of "collateral damage" may be gravely immoral. At least, in the days of world war 2, the carnage was difficult to hide. Today, thanks to technology and the media, we are inclined to view war as one giant video game, abstracting from human suffering. Just as in a game, "surgical" bombs take out their targets in a "precise" manner. But war is not like that, and we (as a society) often turn a blind eye to this messiness, and we do not want the tranquility of our live shattered by such images. Commentators decry Al Jazeera for showing images of death and suffering from the American war machine on TV, and the domestic media refrains from showing them. There is a reason that the Church notes that the bar on on the proportionality consideration is set higher with the destructive capacity of modern weapons. And yet, in contemporary society, there is often a feeling that the bar should be lowered.
In conclusion, the bombing of Germany killed 600,000. According the the British medical journal, The Lancet, the Iraq war killed 655,000. Even if the American bombing of Iraq did not target civilians in the way that the forefathers did in Germany, can we simply appeal to proportional considerations to defend this body count? I would submit that this is a gross abuse of just war theory, and the overarching principal of double effect, to make such an argument.