I think it all depends on the actual process of how targets were chosen (the actual targets, Hiroshima and then Kokura/Nagasaki, not the overall list). I actually have no idea who picked targets, or how they did it. If it was Truman, Stimson, and a few advisers, you're probably right. If not, then maybe not, especially since Kyoto was originally the big target that was really considered perfect for nuclear immolation.
Solomaxwell6,
Rhodes'
The Making of the Atomic Bomb discusses this at length.
There was a fairly scientific process involved in creating the target list. A working committee of scientists from the project, USAAF officers, intelligence officers, and experts on Japan produced a list from which Stimson and a few others could then remove possible targets. FDR would have had veto power too and Truman actually did, but in practice the president merely rubber stamped the list presented to him.
We need to remember that the reasons for each selected target were an important part of the list. Stimson, Truman, and the few others with veto power weren't given a list of a dozen cities without explanation for their inclusion.
I've heard the honeymoon story before with regards to Stimson, but I've never read it any serious study of the bombings. The usual explanation for Stimson removing Kyoto is given as concerns over "cultural heritage", something that seems rather odd when you remember Dresden.
I've seen a map of the Home Islands, less Hokkaido, prepared by USAAF during the war which lists major Japanese cities and their 1940s American counterparts. The list supposedly took population, war production, bases, and other factors into consideration when determining the equivalencies. On the list Hiroshima is Seattle, Nagasaki is Akron, and Kure is Toledo. Oddly enough, while the map was prepared for conventional bombing, Kyoto doesn't appear on it either.
A final word about Operation Downfall. Richard Franks and other historians have been writing since the early 90s at least that, as originally planned, Downfall
would not have been launched in the fall of 1945 even if the Bombs had failed. While the Joint Chiefs had agreed to disagree in June and authorized planning for Downfall, the argument over actually launching Downfall had yet to begin. King, fully supported by Nimitz, was dead set against it, Spaatz supported King, and Marshall was wavering thanks to the mounting intelligence confirming a massive IJA build-up on Kyushu. Only MacArthuts was in still in favor of the Olympic portion of Downfall and he might have had his own reservations about the follow on Cornet component.
Bombs or no bombs, the US was not going to storm ashore on Novemeber 1st, 1945. As Amerigo examined in his recent thread on this topic, only a Soviet invasion of Hokkaido might have caused the US to land in the Home Islands.
Bill