This talks a bit more about the issue.
The atomic bombs served two purposes:
- Demonstrate our power to Russia
- Try to get a Japanese surrender prior to Russia involvement in the Pacific theater.
The second goal obviously failed as Korea was split and China still has strong Russian ties. The first goal arguably failed as the use of the atomic bomb did more to make Russia angry than anything else. It is a tragedy that Japanese civilians were the victims of the weapon demonstration. The real world equivalent of Alderaan, if you will. Hmm... brings up some interesting things to think about. The Third Reich has been the goto comparison of the Empire, but there are a lot of similarities to the United States as well...
The only reason Japan surrendered was because Russia was freed up from its European conflicts and was mobilizing against Japan in the East. If the firebombing of Tokyo wasn't enough to cause a surrender out of the government's pity for its civilian population's plight, why would the nukes do that? And japan was already making overtures for peace before the nukes. It was mass murder and entirely inexcusable.