Counterfactual history, the great what-if game, has generally skipped over the massacres of Hiroshima and Nagasaki.

What If Japan Won At Midway? What If D-Day Had Failed? What If the Berlin Blockade Went Hot? These are all plausible World War II scenarios. As such, each was fleshed out in Robert Cowley's 1998 anthology, What If? The World's Foremost Military Historians Imagine What Might Have Been. But not "What If Truman Did Not Drop the Bomb?" How come this military teaser is missing from the counterfactual playbook?

The difficulty with the no-bomb theme goes to banality. Everybody knows what would have happened to Japan in August 1945, if President Harry Truman had held back the ultimate weapon. As agreed at Potsdam, Stalin declared war on Japan on August 9 and the Red Army immediately rolled over enemy forces in Manchuria. The Soviet invasion of the homeland was just around the corner. So too, the inevitable surrender of Japan.

There is nothing controversial about this speculation. Truman made the prediction himself in his Potsdam diary. Commenting on Stalin's pledge to enter the war in August, Truman wrote: "Fini Japs when that comes about." A classified 1946 War Department study examining the what-if-the-bombs-weren't-used premise concluded that it was "almost a certainty that the Japanese would have capitulated upon the entry of Russia into the war. ..."

So much for the fairy tale that Hiroshima and Nagasaki were nuked to save "half a million American lives," as Truman claimed in his memoir, Years of Decision. (Churchill's figure was "a million American lives" in Triumph and Tragedy.)

Let's get real: putting aside the Soviet factor, D-Day in Japan was not scheduled until November 1, more than three months after Truman ordered his atomic solution. So there was plenty of time for diplomacy. Myriad peace feelers were already in the works.

The major hang-up was the demand for unconditional surrender. The Japanese feared the end of Emperor Hirohito, their Jesus Christ. When the Potsdam Declaration did not specify otherwise, the enemy dug in.

No problem. Truman was flexible behind closed doors. There was political advantage on the homefront in demonizing Hirohito, whom many Americans considered a war criminal. Yet Truman realized, with prodding from the Joint Chiefs of Staff, that cutting off the Emperor's head was a dumb military move. Nobody else had the authority to quell Japanese soldiers and give surrender legs.

In late May, weeks before the successful Trinity test, the Truman okayed drawing up language guaranteeing the status of the Emperor. The suggestion came from Acting Secretary of State Joseph Grew, former ambassador to Tokyo. "A sound idea," recalled Truman in Years of Decision.

It follows that Truman, sans bomb, would have played the Hirohito card eventually rather than invade. How can we be sure? Truman virtually said so. If the bomb had fizzled at Trinity, he wrote in Decision, "then it would be even more important to bring about the surrender before we had to make a physical conquest of Japan."

And let's not overlook the fact that Truman accepted Japan's conditional offer of submission post-bomb after the invasion had faded from the picture. On August 10, Japan submitted to the terms of the Potsdam Declaration except "with the understanding that the said [Potsdam] Declaration does not compromise any demand which prejudices the prerogatives of His Majesty as sovereign ruler."

Truman swiftly closed the deal, letting the criminal leader off the hook. "[I]n a single day it proved possible to reconcile the concept of unconditional surrender with retention of the emperor," observed McGeorge Bundy cynically in Danger and Survival: Choices About the Bomb in the First Fifty Years.

A mountain of evidence against the military necessity to destroy Hiroshima and Nagasaki has not deterred prominent American historians from adopting Truman's saving-the-boys line. Last week Stephen Ambrose rhapsodized the Hiroshima massacre on The NewsHour With Jim Lehrer. He praised Truman for pulling the nuclear trigger, thereby preventing "an American invasion of the home islands, which would have been the biggest invasion ever, and would have lead to the greatest battle that has never been fought, the Battle of Tokyo."

David McCullough expressed a similar thought in Truman, while adding a political twist: "And how could an American President ... answer to the American people if when the war was over, after the bloodbath of an invasion of Japan, it became known that a weapon of sufficient to end the war had been available by midsummer and was not used."

Arthur Schlesinger got more explicit in his autobiography, A Life in the Twentieth Century: "And suppose Congress and the American people learned that Truman had at his command a weapon developed at tremendous cost to the American taxpayer, and he had refused to use it? Truman would have been held personally accountable for the awful waste in American lives, and he almost certainly would have been impeached."

"The Battle of Tokyo"; "bloodbath"; "impeachment" Who are Ambrose, McCullough, and Schlesinger kidding? Their bad faith rivals that of the Japanese historians who whitewash the Rape of Nanking.

Nonetheless, the latter pair were right in one sense. Bracketing the all-important Russian factor, Truman would have had a hard time explaining why he sent "a half million" soldiers into Japan's valley of death--period. Remember, the Bombs of August were not the only options facing Truman in the summer of 1945. If he were impeached, he would have to testify why he rejected peaceful alternatives (e.g., demonstration, strict military target, and changing surrender terms) urged by Army Chief of Staff George C. Marshall, Secretary of War Henry L. Stimson, Assistant Secretary of War John McCloy, Secretary of the Navy James V. Forrestal, Undersecretary of the Navy Ralph Bard, and FDR's and his White House Chief of Staff Admiral William D. Leahy.

A note to the reader: If you are inclined toward Truman's side, ask yourself two questions: (1) What high-ranking World War II generals and/or admirals have recorded support for the obliteration of Hisoshima and Nagasaki? (2) What Churches or moralist or ethicist has ever blessed the same?

A note to the reader: If you are inclined toward Truman's side, ask yourself two questions: (1) What high-ranking World War II generals and/or admirals have recorded support for the obliteration of HIROSHIMA and Nagasaki? (2) What CHURCH or moralist or ethicist has ever blessed the same?