I think that it was a good strategy. It sent two clear messages. One, it told other countries that we were not afraid to protect ourselves and our allies at all cost. Second, it told us that we should never do this again. Once is enough for a nuclear bomb. The horrifying images of people almost literally evaporating because of the radiation and heat was so moving that was like a firefighter's demonstration, except in real life (you know, when they purposefully fill the gas tank wrong and the car lights on fire or something like that - the message being not to do this). It was drastic, but it was necessary and as fremlinc said, it probably saved more lives than it destroyed.