Easy arguments to counter;
1. While no Japanese officer of note ever surrendered his troops, starving, ill-equipped Japanese troops with inadequate weapons may have stayed in their foxholes to die valiant deaths,their defeat was a foregone conclusion. If you measure war simplitically in terms of how many of the enemy you kill, you would be inclined (as you are) to build the Japanese of 1945 up into a major power.
I remind you that at the time of surrender, 2/3 of the Japanese army was still in the field,totally unengaged by any Allied force of consequence and cut off from the Home Islands, unable ot come to their defense, and incapable of offensive action. You cannot fight wars defensively, so the Japanese were done. Through and through.
Starvation was an even more critical factor. It was known (form the same code intercepts that you cite) that Japanese food shortages were crippling the country. SO were shortages of critical materials (iron ore, brass, oil, bauxite, aluminum, etc, etc). The capacity to continue to feed the population, supply the military, and continue war production were approachiing nil. Once the ready-to-hand stockpiles of materials were used up, Japan would be defenseless. The question in this reagrd was how long the US Navy (which had Japan completey bloackaded) could continue out against the Kamikazes, while waiting for the Japanese to finally run out of the means to continue fighting.
2. No fewer than THREE Japanese surrender offers were tendered from May to July, 1945. One through Moscow (which never passed it on), one through Switzerland and another through Sweden (and the Magic intercepts show all of these, in minute detail, as well). The reason why they were not entertained (or entertained seriously in the case of the negotiations in Bern with Allen Dulles) was because the terms under which these surrenders would be effected would make a shambles of the united Allied front and the concept of "Unconditional Surrender".
If anyone was really interested in ending the war free of political constraints (that is, just for the sake of ending the conflict), a Japanese surrender was possible months before Hiroshima.
Going back to Sherman, if you don't consider rail lines and hubs, ports, bridges, shipyards, armories, farms and factories to be legitimate military targets, then I'd be interested in just you think are legitimate military targets. The point is that while Sherman inflicted devestation, there was no policy of deliberately killing civilians in order to "degrade the enemy's war effort" or "break his morale".
Remember, they started the War to begin with.
Regardless of what you may have read in Gullible's Travels, and I am quite sure you cannot be swayed by the facts, but what follows is the real situation at the time.
From American Caesar, by William Manchester, Copyright 1978.
Page 510 of the paperback edition:
Meanwhile Hirohitos generals, grimly preparing for the invasion, had not abandoned hope of saving their homeland. Although a few strategic islands had been lost, they told each other, most of their conquests, including the Chinese heartland, were firmly in their hands, and the bulk of their army was undefeated. Even now they could scarcely believe that any foe would have the audacity to attempt landings in Japan itself. Allied troops, they boasted, would face the fiercest resistance in history. Over ten thousand kamikaze planes were readied for Ketsu-Go, Operation Decision. Behind the beaches, enormous connecting underground caves had been stocked with caches of food and thousands of tons of ammunition. Manning the nations ground defenses were 2,350,000 regular soldiers, 250,000 garrison troops, and 32,000,000 civilian militiamen a total of 34,600,000, more than the combined armies of the United States, Great Britain, and Nazi Germany. All males aged fifteen to sixty, and all females aged seventeen to forty-five, had been conscripted. Their weapons included ancient bronze cannon, muzzle-loading muskets, bamboo spears, and bows and arrows. Even little children had been trained to strap explosives around their waists, roll under tank treads, and blow themselves up. They were called Sherman carpets.
This is true, but is it any more humane to starve civilians than to bomb them? Continuing the blockade and the resulting starvation would have spread the deaths throughout the whole nation and greatly increased the their number. Less Japanese died because the bombs forced their surrender.
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.