[hollerith]

> the two [nukes] which were used were a net benefit in terms of what it would have cost (in both American and Japanese lives) to invade the islands.

There was no need to invade the islands. For the last year of the war, the Japanese had severe problems importing supplies. A significant fraction of their imports were coming in on tiny wooden ships: larger ships and steel ships would probably be sunk by US submarines or US aviation before making even a single delivery, and Japan had almost none left. The US could have simply waited and gotten the same result that they got with nukes. The reason it did not wait is worry that Stalin would invade northern Japan.

The first sentence of the wikipedia page on mining in Japan is, "Mining in Japan is minimal because Japan does not possess many on-shore mineral resources". Although the Japanese homeland does have coal reserves, the extraction costs are much higher than they are in the US and in Europe. It has and had very little petroleum reserves. The wikipedia page I mentioned says that "in 1941, Japanese petroleum production was . . . 0.1% of world petroleum production" and that the US produced about as much petroleum in a day as Japan did in a year.

[learc83]

I agree that the decision to use the bomb wasn't purely (probably not even mostly) based on the desire to limit loss of American and Japanese life. I'm also not saying I necessarily agree with the decision, but an extended siege would surely have caused massive food shortages. By the end of the war Japanese daily rations were already barely above the minimum long term daily requirements, and by 1946 even with US aid, rations were at 65% of minimum daily requirements.

I don't know how many Japanese would have died because of a siege, but it seems likely that if the siege took an extended amount of time, it would be more than died during the bombings.

Additionally in the alternative scenario where the Soviets invade, you'd still likely have a higher death toll. And there is also the continuing deaths of Civilians and POWs in Japanese occupied Manchuria that would have continued until the Soviet invasion was successful.

I don't think I could order a nuclear attack or support a politician who did--but from a purely utilitarian perspective, it's not an easy decision.