Kristof over at the NYT pretends that that there's this huge contigent which objects to the US bombing of Hiroshima. As always, there are of course such people but I really have never been aware that a consensus had formed that it was an unforgivable act.
Nagasaki is more debatable... I'm actually of the opinion that it was probably perfectly justifiable given what they knew at the time (how damaging nukes were, the likelihood of surrrender by the emperor without it, etc... ) , and even quite likely justifiable even with hindsight, but I recognize there is legitimate debate on this topic.
The weird thing is that I mostly agree with Kristof's ultimate point, I just don't understand why he needs to construct a largely mythical antagonist in order to make it.