The only moral justification I know for the bombing of Hiroshima wasn't one anybody made at the time. Once nuclear weapons were a thing, it was only a matter of time until someone used one. The United States used one pretty much right away, when the yields were relatively low, and even that was enough to devastate an entire city in a flash. The Soviets had a bomb of their own four years later and the nuclear arms race began in a sprint. I think it's amazing that the Cold War never got hot considering that both sides had a terror of one another and apocalyptic arsenals pointed at each other for almost half a century, but I also think I know why: the world already had a pair of real and horrifying examples of what these weapons could do. People could already see the magnitude of destruction and the poisonous slow death of the victims. It's about as horrible as you can get.
Imagine what might have happened if America and the Soviets built up their ICBM arsenals into the thousands, with multiple megaton warheads, and neither side had any more than a theory of what the aftermath of a full-scale war might be. There's no way to know for sure, but I think Hiroshima was, in retrospect, an inadvertent sacrifice which may have saved all of humanity from annihilation. Nagasaki is harder to justify, if justification is even possible.
Imagine what might have happened if America and the Soviets built up their ICBM arsenals into the thousands, with multiple megaton warheads, and neither side had any more than a theory of what the aftermath of a full-scale war might be. There's no way to know for sure, but I think Hiroshima was, in retrospect, an inadvertent sacrifice which may have saved all of humanity from annihilation. Nagasaki is harder to justify, if justification is even possible.
