Oh, you mean you can predict what would have happened if the US didn't use nukes?
Even if you were right, it's still not enough to justify the use of nuclear bombs. It should only be used as a last resort and in this case it was far from being the last resort. There is no situation that can occur on Earth, other than an alien invasion, that can justify the use of nuclear weapons.
Above all else, it's a cowardly act. It's like giving someone a low blow in a fight. You know you can't win or you simply don't wanna put any effort into it, so you cheat your way out. They're called America's Greatest Generation, but they've made the worst mistake in the history of mankind.