I think there is a category of actions which are never justified, no matter what the consequences. And yes, I think that the bombing of Hiroshima and Nagasaki fall into that category.

If that can be justified on a lesser evil basis (and I accept that many, perhaps most, people think that it can be), it seems to me that there can be no conceivable human action or atrocity which could not in principle be justified on that basis. I found that frightening, and in one way it is a new way of thinking for a society. In the past people have acted in accordance with this, but have tended to fight shy of claiming that such actions are ethically justifiable.

It occurs to me that the thought experiment I suggested about a situiation where peace was to be bought at the expense of publicly torturing a child to death was reminiscent of a short stoty by Ursula K. Le Guin - "The Ones Who Walk Away from Omelas". Well worth reading.