[Enchante]

So a continuing blockade leading to starvation for millions, plus the likely casualties on both sides from an invasion, is morally preferable to the use of the 2 atomic bombs?

The Japanese peace feelers were not taken seriously for good reason, not solely because of the declared Allied policy of unconditional surrender but for the underlying historical lessons that policy reflected: that anything less than a complete and catastrophic defeat for each of the Axis powers would just lead to a re-building phase and a renewal of war at a later date.

p.s. If we extrapolate from the death tolls on Okinawa (21,000 US and 120,000 Japanese dead), any invasion of the home islands would have been looking at 10x those casualties. The atomic bombings saved vast numbers of Japanese lives, although I'm sure that was not foremost in the minds of US policymakers at the time.

[Enchante]

"...any invasion of the home islands would have been looking at 10x those casualties"

Should have said at minimum 10x those casualties -- of course, many estimates ranged to at least 1/2 million to 1 million US dead and several million Japanese dead. Sure, one can say that all such projections were very speculative, but there was no rational projection in 1945 that said there would not be enormous casualties on both sides, far surpassing what could be expected from the two atomic bombings, if the atomic bombs were not used.