I can see it now -- I think.
It's on the right-hand page of a book by or about Winston Churchill, and it is a quotation by Churchill on the subject on war -- specifically, what happens to a civilized society when it goes to war with a barbarous one. I can't find it (yet), but what I remember as being the main point was that if -- if -- the civilized society is to prevail over the barbarous one, it will necessarily and tragically be degraded by the experience as a vital cost of victory. Partly, this is because civilized war tactics are apt to fail against barbarous war tactics, thus requiring civilized society to break the "rules" if it is to survive a true death struggle. It is also because the clash itself -- the act of engaging with the barbarous society -- forces civilization to confront, repel and also internalize previously unimagined depredations. This is degrading, too.
In Churchill's era, the more civilized world of the Allies was necessarily degraded to some intangible extent by what it took to achieve victory over barbarous Nazism. For example, bombing cities, even rail transportation hubs, lay beyond civilized conventions, but this was one tactic the Allies used to defeat Hitler. However justifiably, civilization crossed a previously unimagined and uncivilized line to save, well, civilization. Then there was Hitler's Holocaust -- an act of genocide on a previously unthinkable scale and horror. Who in the civilized world ever imagined systematically killing millions people before Hitler? And who in the civilized world retained the same purity of mind after? Civilization itself was forever dimmed.
The question is, did, for example, bombing Dresden to defeat Hitler or, in the Pacific War, dropping two nuclear bombs to force Japan to stop fighting, make the Allies into barbarians?
I think most people would still say, "of course not," and argue that such destructive measures were necessary to save civilization itself -- and certainly thousands of mainly American and Allied soldier's lives. But if this argument continues to carry the day, it's because we still view that historic period from its own perspective: namely, as one in which Allied lives -- our fathers, husbands, brothers and sons -- counted for more than Axis lives, even those of women and children.