If you think they did not save lives what action do you think would have been superior?
Not doing anything?
Stage a coup with the dissatisfied masses?
I am not a military planner and even if were I neither lived during WW2 nor studied it in such depth of detail to tell you the "awesome tactical plan in hindsight X" which is undoubtedly superior to whatever savage gaijin of the past century could've thought of.
/sarcasm
If the nukes were not used to end the war why were they not employed alongside the invasion as some proposed?
This is a loaded question.
Thankfully I have the answer. Why do you think USA only planned to drop two nukes? They had more in the making.
There's no "if" neither "or" in this scenario. Dropping nukes before the invasion is not exclusive to the idea to dropping nukes
during the invasion, as well.
Edit: I do not like your wording saying a bombing will kill 90% of a city, it may destroy large amounts of structure but would not approach anywhere near that in terms of lives lost.
Yeah, lives lost is a bit harder to estimate with the percentages. Large cities were less populated already out of caution as US air raids targeted them, for example.
But the bombs dropped at Hiroshima destroyed about 60-70% of the city while fire bomb raids could approach 97% or so.
Look, I am not using the nuke as a label to declare USA's actions in WW2 as a special kind of evil. Shocking, I know. There's quite a big stigma on nukes nowadays with a good reason. But considering they were in the middle of the mess called total war it was really just the difference of dropping one super bomb instead of many smaller ones.
I'm of the opinion that the Japanese recognizing the futility of their plans and surrendering was most likely a matter of "when", not "if". I also rather disagree with the notion that the atom bomb had no influence upon that. Looking at the Japanese decision making apparatus, it is clear that the atom bomb accelerated the end of the war war by a noticeable amount of time (we're talking some months here), and in doing so saved more lives then it took. My attitude is actually the same for the Soviet invasion of Manchuria...
Speaking of which, one of the interesting things I recently realized is that much the same accusations that is levied against the atom bomb can likewise be hurled at the Soviet invasion of Manchuria.
Citations needed. Soviets were already invading Manchuria and that pretty much bound the hands of the Japanese political leadership.
For a while they didn't fight for victory but for peace talks where they can preserve their government and preferably avoid trial. With the Soviets at their doorsteps IIRC things pretty much were over within days, not months.
Japan capitulated to the USA before they'd be forced to do that to the Soviets or both.
I am pointing that the atomic bombings was hoped to end the war, many argued against their use in strategic targets like they were because the production of nuclear weapons was slow and it was considered every one would be needed for Downfall.
Operation Starvation and Downfall were combined looking at tens of millions of Japanese deaths since the next step in Starvation was to destroy every field the USAAF could. Downfall was expected to face almost every civilian to be armed and attacking in human wave assaults, mass kamikaze attacks by the remaining Japanese aircraft, and one final charge by the IJN with every remaining large ship having just enough fuel to reach expected landing areas.
Now not every civilian would willingly join the attacks but millions would, millions more would be swept along with them, and those who refuse would face repercussions from the true believers.
Operation Downfall was a measure of last resort. And believe me if it were necessary then Japan wouldn't have been scared of nukes, either.
The emerging Soviet push and Japan's intense fear of dealing with them would've forced the leadership to capitulate to the USA, anyways.
