I talk in more (somewhat ramble-y) detail here [0], but I think I can put a more succinct version of the anti argument here, the main argument is that to morally justify the extreme act dropping atomic bombs on those cities requires an extreme set of justifications to the level of "it was the only option short of a bloody millions dead between both sides home island invasion" that history doesn't necessarily support.

The core thrust that undermines the this or that between bombs and traditional invasion justification for dropping the bombs is that a) the Emperor was already exploring possible peace deals and b) ultimately the Emperor was able to override the extreme militarists in the war council and accept the peace after the bombs. A lot of the pro-moral-bomb argument presupposes that the shock and awe of the atomic bombs were a prerequisite for the change in stance and that anything short of a full invasion of the home islands would not achieve shift large enough to get to a peace deal. (and that to achieve that impact required them to be used on a city)

Ultimately I think (and I know this is extremely hard to prove ahistorically) a naval blockade and shelling/arial campaign that devastated what little military might Japan had left would have lead to the same shift as the bombs and that the casualties from that would be lower or at least less morally weighted as the intentional atomic bombing of Hiroshima and Nagasaki. When that shift would happen and how to weigh the deaths morally are going to vary a lot from person to person though and I accept that.

> Even after all this, hardline military officers attempted a violent military coup to destroy the Emperor's recorded surrender broadcast and keep the war going.

A coup that ultimately fails though. I don't think anyone really argues that there weren't fanatical elements remaining even after the bombs were dropped. Their existence doesn't mean peace required the bombs however, the big question is what were the conditions that would reduce their power to the point the peace could be accepted. We have one example in the bombing but that doesn't mean that was the only option.

[0] https://news.ycombinator.com/item?id=49757977

I think very few people on the anti-bomb side would seriously argue there wasn't a split in the Imperial government and a lot of preparation going into defending against a potential US invasion attempt. At the same time however there were the beginning of diplomatic efforts to explore a negotiated peace from minority factions in the Japanese government partially backed by the Emperor, these (to me) undermine the "it was the only option" argument supporting the bombings morally. I found this article that talks a bit about the feelers (even though it gets side tracked about a supposed early-1945 prototypical peace "offer" that closely matched the eventual status post war, though that's an interesting read and an important bit of info about how to treat and examine reports of things like that). [0]

The main thrust of the anti-moral-bombing argument is essentially that the MAGIC intercepts we know happened for sure of their early diplomatic feelers indicate that the Emperor and some minority factions were beginning to develop the terms for a possible surrender and that combined with the main reasons for the US bombing not being directly oriented towards defeating Japan but were already looking to their next adversary, the USSR, weakens the argument that the bombing was ultimately more moral way of ending the war. We know for sure from Truman et al's own writings at the time show that their only concern wasn't the least bloody end of the war with Japan and they wanted to demonstrate the bomb to the USSR, I think that's pretty undisputed history even by the pro-moral-bombing side of the argument.

I tend to agree that it's unlikely Japan would have been able to stand up to a US blockade when we were already able to safely park battleships off their coast before the bombs were dropped and ultimately the Supreme War Council would have been overruled by the Emperor the same way they were after the atomic bombs were dropped. How quickly would the pro-negotiation side have gained power with a blockade of the home islands? That would have been a pretty safe operation for the US at the time.

The biggest question marks in the whole thing are largely impossible to answer how many more defeats would the militarist side have to suffer before accepting a surrender that looks like the eventual post war status. The insistence on unconditional surrender is also a thing that's difficult to weigh morally. If the US insists on a condition it knows is unacceptable how much does that shift the moral blame for Japan not accepting the ultimatum of an "unacceptable" condition or bomb?

Sorry if it's a bit jumbled, I'm bouncing between work and this and I'm not a great essayist to begin with.

Too long; You rambled too much there in the middle: the main argument of the antibomb remains that it's unlikely that a full or even partial invasion of the home islands would have been ultimately required and the atomic bombing of civilians is so morally bad that it requires an iron clad "there was no other option to end the war" (or the only alternatives were far bloodier; eg a full home island invasion) which the Japanese feelers about negotiating a peace undermines.

I think ultimately if we could part the curtains of time for both sides and show the post war outcome to both sides Japan would have accepted a surrender that lead to that future.

[0] https://blog.nuclearsecrecy.com/2022/05/06/did-the-japanese-...

Should Japan have A-bombed the US then? https://www.theatlantic.com/national/archive/2012/01/what-am...

3-days is a pretty short time for such a major shift in politics for starters. Would a 3rd or 4th have been justified in the 6 day gap before their August 15th surrender announcement if the US had had them available?

Also the justification for the second bomb, that it was required to demonstrate it wasn't a one off doesn't require the that bomb be dropped on a second city either. The main thrust isn't that the bombs weren't effective it's that the extreme nature of the act requires extreme justification bordering on it being the only option but for a bloody home island invasion. See my other long posts about the anti-moral-bomb argument in this thread, I don't want to duplicate them here to avoid spamming the thread.

> One day people will make this claim about Russia in their current Ukraine war

They might, it would be a sore excuse to nuke Russian territory or bomb Moscow a-la Dresden in 1945. The fact that Americans cannot imagine resolution to war without nuclear violence is exactly how Crimea was annexed and lost. If you ignore proportionality, then your adversary can test your patience and win every time.

This is why asymmetric warfare is so popular in Russia and China, and why it pisses off Americans so consistently. Nuclear weapons give nations a false sense of security, it doesn't protect you against subtle escalation like widespread corporate hacking, political blackmail, proxy conflicts, border harassment or industrial overmatch.

The complicating part to that is there's not the same Supreme War Council populated by militarists vs the Emperor split in modern Russia, there's just Putin. To match scenarios there would have to be an oligarch council in Russia pushing continuing the war while Putin put out feelers and that's not what's happening.

Also nothing about the anti-moral-bomb argument hinges on apologetics for Japanese actions just arguments that the bombs were unnecessary to achieve the end to the war. The only assumption is that there was some set of conditions and peace deal short of the two bombs that would lead to the emperor overriding the war council and surrendering.

Even with the first bomb I wonder if they could have handled it a bit differently. Maybe scuttle a ship with it in the middle of the Tokyo bay, then drop a dud bomb directly onto the imperial palace with a warning painted on it. Seems like immediately after the bombings in hiroshima and nagasaki there was still quite a fog of war going on initially about what even happened. Making the sun appear in the middle of the tokyo bay would have been indisputable however. You'd get the blinding flash, the shockwave, the awe of the cloud, and everyone including everyone in government would not only witness it (anywhere with a window would have gotten the at least the flash), but survive, and do something about having witnessed it.

Of course 1940s thinking of the world was a bit less restrained when it came to the question of wasting a quarter million people in an instant. One wonders if the US felt the bombs were necessary to use with the war already won by that point to have sort of established precedent to use them in future conflicts. The quickness between targets would say as much as well: this is just another bombing run no different than an incendiary run a few days apart from another. After all, that's exactly what MacArthur intended to do in Korea. They were probably desperate to ensure their miracle weapon, one that took so much investment and effort and had so many careers staked in its success, would not end up like chemical weapons where it was verbotten to use even by the nazis.

If the need was /just/ to demonstrate the existence of a second bomb implying a continuous pipeline/supply, that didn't have to happen in a city.