Marking the anniversary of the bombing of Nagasaki on August 9th, Catholic apologist Karl Keating discusses the bombing in light of Catholic just war principles in his latest e-letter, with a stern warning to "anything goes" conservatives:
Catholic moral principles are easy to apply to other people, difficult to apply to ourselves. This is as true in public life as in private life. During World War II our enemies did atrocious things on the battlefield, to conquered nations, and even to their own people. Many of these evils we knew about during the war; others came to light only after the cessation of hostilities.
Even those evils we knew about during the war were so prevalent and so gross that, to many, it seemed permissible, for the duration, to lay aside a principle that we insisted be followed by our enemies: The end does not justify the means.
Rephrase that in Catholic terms: To achieve a good, you may not perform a sin. To provide your family financial security, you may not rob a bank. To protect your wife's health, you may not abort the child she is carrying. And to defeat an enemy in war, you may not violate just war principles. But we did--and more than once, sad to say.
The atomic bombings of Nagasaki and Hiroshima, like the fire bombings of Dresden and other German cities, cannot be squared with Catholic moral principles because the bombings deliberately targeted non-combatants. The evil done by our enemies did not exonerate us from the moral law. Their evils did not provide us justification for evils of our own. Being a Christian in peacetime is difficult; it is more difficult, but even more necessary, in wartime.