Perhaps, but the USSR declared war on Aug 7. Hiroshima was Aug 6. Japan surrendered Sept 2. Also consider. The USSR declared on Aug 7 because they wanted

Perhaps, but the USSR declared war on Aug 7. Hiroshima was Aug 6. Japan surrendered Sept 2. Also consider. The USSR declared on Aug 7 because they wanted to get their bite out of Japan before it was too late. So in some sense the bomb hastened their entry, which hastened the end of the war... All I can say is, I'm glad I'm not the one who had to make these decisions in real time.