I think the Americans truly believed they had no other choice at the time. Not saying that the use of nuclear weapons is ok. Hopefully the world has learnt a lesson from WWII and we never have a third with even limited use of any nuclear devices.

Agreed. They had just been victims of a shock and awe attack on Pearl Harbour. They responded in kind, as they saw fit, and to bring a resolution to the war. OK, it was the ultimate retaliation, but it did bring WW2 to a close. And as you say hopefully this will show future generations that another world war is best avoided, and that it is in all of our interests to pursue peaceful co-existence and development.