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The moral issue
Was America justified in dropping the bomb? Was it simply a new toy that the Americans had spent millions developing and were therefore determined to try out? Was its propaganda importance in the forthcoming Cold War the real motivation for the bombing? There are a couple of things worth remembering. The defeat of Japan was unlikely to come quickly. The martial code that inspired kamikaze pilots meant that many would prefer to die than surrender. Given that the Japanese occupied many strategic sites in the South Pacific, there were bound to be high casualty rates on the American sides if a series of amphibious landings were to be attempted. It is worth remembering that the most destructive bombing during WWII did not take place at Nagasaki or Hiroshima, but on Tokyo using conventional weaponry. Operation Meetinghouse, which was conducted on the night of 9–10 March 1945, is the single most destructive bombing raid in human history. Some modern post-war analysts have called the raid a war crime due to the targeting of civilian infrastructure and the ensuing mass loss of civilian life. The US Strategic Bombing Survey later estimated that nearly 88,000 people died in this one raid, 41,000 were injured, and over a million residents lost their homes.
These casualty and damage figures could be low; Mark Selden wrote in Japan Focus:
The figure of roughly 100,000 deaths, provided by Japanese and American authorities, both of whom may have had reasons of their own for minimizing the death toll, seems to be arguably low in light of population density, wind conditions, and survivors’ accounts. With an average of 103,000 inhabitants per square mile (396 people per hectare) and peak levels as high as 135,000 per square mile (521 people per hectare), the highest density of any industrial city in the world, and with firefighting measures ludicrously inadequate to the task, 15.8 square miles (41 km2) of Tokyo were destroyed on a night when fierce winds whipped the flames and walls of fire blocked tens of thousands fleeing for their lives. An estimated 1.5 million people lived in the burned out areas.
The casualty figures for Operation Meetinghouse of around 100,000 deaths and 41,000 injured makes it the most destructive single bombing raid WWII. Hiroshima and Nagasaki which resulted in 66,000 and 39,000 dead respectively and a further 69,000 and 25,000 respectively. The Anglo-American bombings of Dresden (27,000 deaths) and Hamburg resulted in 27,000 and 37,000 deaths respectively, but hundreds of thousands of injuries. To real significance of Hiroshima and Nagasaki lies in the fact that the Hamburg bombing involved approximately 3,000 aircraft and 9,000 tons of bombs. The devastation of Hiroshima and Nagasaki, on the other hand, resulted from the use of a single bomb in each case.
A simulation of the devastation that would be wrought were a nuclear device be dropped, can be found on NUKEMAP
RGS History 
