Dropping the atomic bombs made America look like a bunch of irrational cowboys. This was a good thing. The Cuban missile crisis (probably) did not end in nuclear war because the Russians were convinced the Americans were irrational enough to use nukes and had shown this by using them before. Playing chicken after convincing the other guy your irrational may not be a great strategy but it does seem to have worked.

There is a good documentary on the thought processes of those that bombed Japan and were involved in the cuban missile crisis called "the fog of war" excerpt here http://www.youtube.com/watch?v=er2xCn3_QcQ

stefan Thanks for the interesting comment