Hawaii and a lot of other islands would have been theirs. Take for granite we would of won them back eventually, but why would the US waste $40+ million dollars on fighting a war that can easily be prevented by dropping the A-Bomb? There are positive and negative consequences with every action. Killing 1000's of Japs was the consequence, but saving the US 40+ million dollars, and a lot of lives was the reward. So in my opinion, yes, it was ok to kill 1000's of people for our sake... Not to mention, they attacked pearl harbor.