I’m happy Truman dropped the bomb. My Grandfather was a marine in the Pacific during WWII. He most certainly would have been part of the invasion force of mainland Japan, had Truman not dropped the bomb. And if my Grandfather had died, I wouldn’t be here. Also, there’s the fact that there would have been significantly more casualties, if an invasion of mainland Japan had occurred. Certainly more than having dropped two Atomic bombs on Japan.
I repeat a true leader does what he has to to minimize loses of his troops while inflicting the most damage on his enemies including collateral civilian casualties.