Was the atomic bombing justified? Yes, it was. Truman made the right call. The US naval and air campaign against the Japanese homeland, unlike the Allied bombing of Germany, seriously deteriorated Japan's industrial capacity. The strategic bombing of Japan had by mid-1945 probably cut Japanese industrial production in half. Japan was clearly going to lose the war but its leadership had no intention of recognizing that. As the American invasions of Iwo Jima and Okinawa showed, the Japanese were brave, tough, skillful, and determined defenders of their home islands. American military planners looked at the casualties from those two campaigns and extrapolated to what it would cost to invade Japan proper. The US military estimated that there would be at least one million American casualties, plus hundreds of thousands of other allied dead and wounded, and perhaps twenty to thirty times that many Japanese casualties in the case of an invasion. Such a campaign in Japan might take one to two years, would result in the total devastation of Japan, and produce a legacy of hatred and bitterness that would last a hundred years or more.If anything, I probably understated the consequences of not dropping the atomic bomb. The invasion of Japan would have been a calamitous affair from all aspects. I don't think we would have ever had the friendship and alliance we now have with Japan had the invasion occurred. Quite likely we would have had a partitioned Japan, with a Soviet sector and eventually a Korea-type scenario, and very likely continuous guerrilla warfare that could have lasted years after the formal end of hostilities--assuming the invasion succeeded. It is hard to imagine how dire the consequences of that would have been for Japan, America, Asia and the whole world.
Why do I bring this up, yet again? You know why. The revisionists always emerge at this time of year to bemoan the atomic bombings, and they do it without context. I have noted before how at the UN, during the 40th anniversary commemoration of the end of the Second World War, there were speeches, pamphlets, and exhibits that made it seem as though Harry Truman woke up one day and decided to nuke Japan, just because. As a conservative, of course, I have lots of problems with Truman's handling of the domestic economy and of the Korean War, but he made the right call on ending the war with Japan in the fastest and, ultimately, least costly manner for all.