[AChimp]

It's interesting to note that at the beginning of WWII, the bombing of civilians was considered barbaric by all sides. The Nazis opened that door with Hitler's proclamation that he wanted no stone atop another to remain in Britain.

Mesobe is right, though. The Japanese government held out through two bombs. They didn't surrender immediately after the first attack, nor immediately after the second attack. I've even heard that the Japanese even tried a conditional surrender before they gave up completely. Now undoubtedly, there was a big push to surrender right away after they realized what an atomic bomb was, but the people making the decisions still thought they could prevail. I think that alone is an indicator of how long they could have held off a conventional land invasion.

As Max has stated, too, the use of the bomb was partly political (to show the Russians the potential consequences of getting greedy in Europe), but I disagree that the ethics and other options were not considered. The U.S. army spent years developing the bomb and thought about whether or not they would actually use it and where. The scientists working on the project actually petitioned Truman NOT to use it after the Manhattan Project was successfully tested. They knew it was going to be a big bomb, but they had no idea of the actual destruction it could cause.

The locations for the bombings was carefully chosen for dozens of reasons. One of the main factors in the decision was the effect on morale. They also wanted an area that had enough infrastructure to deal a substantial blow to the Japanese war machine and so that they could fly over afterwards and get a really good idea of the its true destructive powers on an inhabited area.

The Japanese would have simply laughed at the bombing of an atoll or rural area and then claimed they could withstand whatever we threw at them.

I think the use of the bomb was a necessary evil, and the images of the actual result of its use against people is probably one of the biggest deterrents of its use against more people in the future.