Among the corrosive lies a nation at war tells itself is that the glory -- the lofty goals announced beforehand, the victories, the liberation of the oppressed -- belongs to the country as a whole; but the failure -- the accidents, the uncounted civilian dead, the crimes and atrocities -- is always exceptional. Noble goals flow naturally from a noble people; the occasional act of barbarity is always the work of individuals, unaccountable, confusing and indigestible to the national conscience. This kind of thinking was widely in evidence among military and political leaders after the emergence of pictures documenting American...