Alex WellersteinVerified account

So they weren't warned with leaflets. The last refuge of the "they were warned" crowd is "well, didn't Truman warn them in the Potsdam Declaration?" Not really — it said, we want unconditional surrender, and the alternative was "prompt and utter destruction."

Is that a veiled reference to the atomic bomb? Probably. But it is one that only makes sense after you know the atomic bomb exists — which was kept a secret. It's not a warning if you can't understand it until AFTER the event you are being warned against.

The US planners HAD considered warning Japan about the atomic bomb, and had rejected the idea. They deliberately kept it secret for reasons both tactical (avoid the bombing planes being targeted) and psychological (they hoped the "shock" would dislodge Japan's high command).

Which is to say, the idea that the cities were warned doesn't even make much sense of the face of it. It's not something that Groves, Truman, Tibbets, or anyone else connected to the bombing program ever claimed. So why are do so many people claim it today?

The answer is pretty clear to me: they think it lessens the moral difficulty of defending the bombing. If we warned them, and they didn't surrender or evacuate, then it's really their fault they died, not ours, right?