My dialogue opponent’s words (originally posted on Mark Shea’s site) will be in blue.
Unfortunately, the errors that many prominent Catholic apologists and writers make in issuing blanket condemnations of the bombings are too many to discuss in an exhaustive manner. So, I will restrict myself to what I think is the most glaring: that we targeted non-combatants. This is not only false, but absolutely impossible when you consider that Japan had complete[ly] erased the distinction between combatant and non-combatant by conscripting practically the entire adult population. Gen. MacArthur biographer Willliam Manchester points out: (by the way, MacArthur vociferously denounced the atomic bombings):
Hirohito’s generals, grimly preparing for the invasion, had not abandoned hope of saving their homeland. Although a few strategic islands had been lost, they told each other, most of their conquests, including the Chinese heartland, were firmly in their hands, and the bulk of their army was undefeated. Even now they could scarcely believe that any foe would have the audacity to attempt landings in Japan itself. Allied troops, they boasted, would face the fiercest resistance in history. Over ten thousand kamikaze planes were readied for “Ketsu-Go,” Operation Decision. Behind the beaches, enormous connecting underground caves had been stocked with caches of food and thousands of tons of ammunition. Manning the nation’s ground defenses were 2,350,000 regular soldiers, 250,000 garrison troops, and 32,000,000 civilian militiamen, a total of 34,600,000, more than the combined armies of the United States, Great Britain, and Nazi Germany. All males aged fifteen to sixty, and all females ages seventeen to forty-five, had been conscripted. Their weapons included ancient bronze cannon, muzzle loaded muskets, bamboo spears, and bows and arrows. Even little children had been trained to strap explosives around their waists, roll under tank treads, and blow themselves up. They were called “Sherman’s carpets.” This was the enemy the Pentagon had learned to fear and hate,a country of fanatics dedicated to hara-kiri, determined to slay as many invaders as possible as they went down fighting. [William Manchester: American Caesar: Douglas MacArthur 1880-1964, pg. 510-511)]
In other words, the entire country of Japan was thus turned into a military base and therefore a military, not a civilian, target. Therefore, given this fact, and following the principle of proportionality (not the same as proportionalism) recognized by the Catholic Church a legitimate moral consideration (i.e. that the only other alternative would have caused more death and destruction on both sides) , it is more than licit for a Catholic to agree with Truman’s decision. [comment on 5-22-08]
I’m curious. I haven’t read this whole combox thread (if I started doing that on this site I’d have time for nothing else). Has anyone asked how an infant or a comatose person or severely retarded or schizophrenic or senile person could magically turn into a “combatant” because the Japanese government said so? Everyone immediately becomes a soldier in one second because the crazy Japanese command in 1944 or 1945 says so? Therefore they can be morally annihilated according to good ol’ Catholic just war theory? [comment on 5-24-08]
[citing William Manchester]:
All males aged fifteen to sixty, and all females ages seventeen to forty-five, had been conscripted. (American Caesar: Douglas MacArthur 1880-1964, pg. 510-511)
In other words, the entire country of Japan was thus turned into a military base and therefore a military, not a civilian, target.
But this proves my point exactly (a contradiction is present here): it means males under 15 and over 60 and females under 17 and over 45, had not been conscripted; therefore, they were civilian targets, which is not in accordance with just war ethics. In addition there were people in the categories I had mentioned: infants, comatose, severely retarded, schizophrenic, senile.Other similar categories would be the elderly in general and the sick and inform (folks like quadriplegics or terminally ill or less sick but confined to bed), who were in no position to fight against anyone; also whatever number of “conscientious objectors” or pacifists who could be found in Japan.
These were all killed alongside the conscripted civilians. This particular defense was always a wrongheaded, confused one. It was when I interacted with you and [so-and-so] on the nuclear issue, and it remains one now. It’s the weak link in your entire argument. Once this is understood, there is little left, and the attempt to transform these horrific acts into justifiable ones in light of Catholic teaching falls flat.[comment of 5-25-08]
Medical personnel is another such “non-military” category. According to one estimate: “Of 2,160 medical personnel in Hiroshima at the time of the bombing, 1,980 were killed or injured.”
Yet another category that should be considered is Koreans who were conscripted against their will into the Japanese military. According to the copiously documented Wikipedia article, “Korea Under Japanese Rule”:
In the case of Korean A-bomb victims in Japan during World War II, many Koreans were drafted for work at military industrial factories in Hiroshima and Nagasaki. There were a total of 70,000 Korean casualties in both cities; 40,000 were killed and 30,000 were exposed to the A-bomb radiation.
One could argue, I suppose, that these are still soldiers, and so, “what’s the beef?” But this misses the point. If the goal is to kill actual Japanese soldiers: the ones who kept the machine going, and who are legitimate targets of military actions, and it involves 40,000 Koreans who were forcibly conscripted, then this is hardly a just response itself, because the target (i.e., these Koreans) are not the ones who are at fault.
It would be like 40,000 American POWs now “recruited” for the Japanese war effort. Do we simply slaughter them, too, in the nukings, as if there is not a qualitative difference, ethically speaking, since the Americans in no way were in any agreement with the Japanese goals? Likewise with Koreans.
The Wikipedia article, “Atomic bombings of Hiroshima and Nagasaki” provides further statistics:
In the spring of 1948, the Atomic Bomb Casualty Commission (ABCC) was established in accordance with a presidential directive from Harry S. Truman to the National Academy of Sciences-National Research Council to conduct investigations of the late effects of radiation among the survivors in Hiroshima and Nagasaki. Among the casualties were found many unintended victims including:
* Allied POWs.
* Korean and Chinese labourers.
* Students from Malaya on scholarships.
* Some 3,200 Japanese American citizens. 
Forgotten Wars: Freedom and Revolution in Southeast Asia, Prologue: An Unending War, Christopher Bayly & Tim Harper, The Belknap Press of Harvard University Press, pp. 3
During the war Japan brought many Korean conscripts to both Hiroshima and Nagasaki to work as forced labor. According to recent estimates, about 20,000 Koreans were killed in Hiroshima and about 2,000 died in Nagasaki. It is estimated that one in seven of the Hiroshima victims was of Korean ancestry. 
Mikiso Hane. Modern Japan: A Historical Survey. Boulder: Westview Press, 1992.
(originally from 5-25-08)