Oh pleeeze, spare us the cliché leftie knee-jerk anti-US revisionist line about the big bad Americans dropping two nukes (which BTW, Canada had a major part in their design & development) on the poor innocent Japanese, just because they could.
There was a conflict going on at the time, you may have heard about it, IT WAS CALLED WW2 and the Japanese started it by a sneak attack on Pearl Harbor.
The 2nd General Army and Chugoku Regional Army were headquartered in Hiroshima, and the Army Marine HQ was located at Ujina port(30% of the total casualties were military). 

As for “Japanese innocence” more Chinese were killed by Japan than Jews by the Nazis. Google “The 3 Alls, “The Rape of Nanking”, “Unit 731, comfort women” , and the Japanese treatment of Allied POWS and see how innocent Imperial Japan was.: http://en.wikipedia.org/wiki/Japanese_war_crimes.

The nukes were a case of what goes around comes around and Japan earned every neutron they received on those fateful days in August.