Actually the threat of overwhelming power did it. Tokyo suffered massive and overwhelming bombing already which they shrugged off, but the idea that we could destroy their cities easily is mostly why they chose to surrender.
What keeps the peace against forces of evil is the threat of overwhelming force, not necessarily the act. The act of force obviously makes the threat more credible, but credibility also requires credible means of force. Nuclear weapons, for example, are no longer credible except in a MAD scenario and we are not suicidal.
The other flaw in your argument is comparing the terrorists to the Japanese. The terrorists may well be "pansies" but the are unfortunately also much less disciplined. When the Japanese government surrendered, most of its fighters surrendered. With Muslim fanatics I don't think that would be the case.
Good point. However, one of the reasons the terrorists hit us is because they know our tactics. "Oh, they won't do anything, or if they do they will do selective strikes, etc.". They didn't believe that we would go after Al-Quada for the twin towers...wasn't that the belief? They though we would cower or launch a couple missiles (Clinton).
My point about carpet bombing is overwhelming force and destruction. No, we should not nuke any country. We are well aware of jetstream and fallout etc... But there are ways of pounding them so bad that you may have well of used a nuke...Daisy cutter and MOAB ring a bell? We can pulverize someone without MAD.
But we won't do that. There is no threat of overwhelming power anymore. Stay away from military targets and you are safe for the most part. The enemy has us figured out better than we have them figured out in many respects.