None are needed. None should be expected. None are deserved.
As the Geek discovered when teaching classes in military and diplomatic history to students who included Japanese kids, the educational system in Japan has sanitized its presentation of the history of World War II to the point of utter absurdity. Intelligent, well-educated young Japanese had never been told, for example, of their country's culpability in the unprovoked aggression against China. Nor had they ever heard of the way in which the Imperial Japanese Army took over foreign policy with the view of inaugurating a period of conquest driven expansion in Asia and across the Pacific.
These students, some of whom had spent a year or more at prestigious Japanese universities, were clueless about the tortured process of diplomatic disinformation which preceded the attacks upon Pearl Harbor, the Philippines, and Singapore. None had the slightest idea that the attack upon Pearl Harbor was carried out without any formal warning or ultimatum.
In a similar manner none had ever heard of the "Rape of Nanking," nor the "Bataan Death March," nor the brutal abuse and malignant killing of prisoners of war in Southeast Asia, Taiwan, Korea, or in the home islands. They were equally unaware of the manner of defense practiced by the Japanese armed forces and the horrific human costs both Japanese and Allied which those defense to the death tactics extorted.
Finally these students, and, by inference the larger Japanese public, had no knowledge of the plans laid by the Imperial high command for the final defense of the home islands. As a consequence, they had no awareness as to the cost in Japanese lives, primarily civilians dragooned into the defense efforts, that would have been had the war not been brought to an end by the twin atomic bombings of August 1945.
Literally millions of Japanese would have been killed in combat operations or would have died from disease or starvation incidental to the protracted war. US planners low-balled the estimate of American fatalities at roughly a half million. (Later, after the victorious Allies had had a chance to review what the Japanese planned and the resources for defense they possessed, it was concluded the Americans would have been lucky to get away with less than a million killed in action or died of wounds.)
As was hoped (but not really expected), the psychological shock of the two atomic bombings brought the Emperor to the side of the outnumbered "peace faction" within the government. This assured the war would end. The change in the mind of the Emperor did what nothing else did, not the first bombing alone, not the Soviet invasion of Manchuria, not the steady march of the Western allies to the home islands--it brought the war to an end.
The two bombs exacted a very large toll of lives. More than the Americans expected since the effects of radiation, both prompt and delayed, were very poorly understood. Leaving aside the delayed impact of ionizing radiation, the butcher's bill at Hiroshima was not out of line with those caused by the "conventional" firebombing of Tokyo in mid-March 1945 and, relative to the population, less than some of the other fire raids.
In any event, the fatalities resulting from the atomic bombs delivered to Hiroshima and Nagasaki were at least one order of magnitude less than the minimum body count which would have attended the execution of operations Coronet and Olympic. It is a truth not a mere assertion that the use of the atomic bombs saved many, many lives compared to the cost of invading.
Like an invasion, the use of a prolonged maritime and aviation imposed siege on the home islands would have strengthened the political hand of the Imperial General Staff, particularly the Army. The Army high command more even than the Imperial Japanese Navy sought a war to the death, a war of sufficient length and cost to the Americans so as to preserve the honor of the Army and the "dignity of the Emperor."
The "dignity" and "honor" might have been preserved. Then again, they might not have been given the American view that the longer the war, the harder the peace.
The atomic bombs, both of them, not just the first one, the Hiroshima "Little Boy," obviated the matter of honor and dignity, made moot the human cost of a longer, harder, infinitely bloodier war. One of the greatest tragedies to ensue was the inability, no, the unwillingness of members of the American Left and the Japanese public to accept that the two atomic bombs were necessary weapons properly employed which served to save lives both American and Japanese.
An even greater tragedy comes in the willful ignorance of the Japanese public regarding their own history. It is this ignorance that propels the desire for an apology from the US for making the war shorter, less bloody.
It boggles the mind to hear demands for an apology. The US should apologize for ending a war which it did not start? A war which was forced on the US, the Chinese, the Australians, the British, the many people of Asia and the Pacific--for this we should apologize? We should apologize for the millions of Japanese then who were not killed because we ended the war by using the bombs--after issuing a clear warning? We should apologize to the many descendants of those undead Japanese who are alive today because we used the bomb rather than let the Army of the Emperor prolong the war to salvage their "honor?"
No apologies are required. None should be expected. None should be desired. And, no American today should even harbor the slightest twinge of guilt over our having ended the war in the way we did.
Certainly those of us who are alive today because our fathers or grandfathers did not die in the projected invasion should not regret but rather celebrate the courage of the Truman administration in making the decision to use the bomb--and end the war.