The atomic bombs that ended World War II killed — by some estimates — more than 200,000 people. In the decades since 1945, there has been a revisionist debate over the decision to drop the bombs.
Did the U.S. decide to bomb in order to avoid a land invasion that might have killed millions of Americans and Japanese? Or did it drop the bomb to avoid the Soviet army coming in and sharing the spoils of conquering Japan? Were the prospects of a land invasion even more destructive than the opening of the nuclear age?
D.M. Giangreco, formerly an editor for Military Review, has taken advantage of declassified materials in both the U.S. and Japan to try to answer those questions. He talks with NPR's Scott Simon about his new book, Hell to Pay: Operation DOWNFALL and the Invasion of Japan, 1945-1947.
As U.S. military planners contemplated a land invasion of Japan in 1943, military units were being held back from possible action in Berlin because it was understood that they would have to be sent to the Pacific.
"There was a very, very tight timetable," Giangreco says. There were "clearly not enough forces in the Pacific."
The participation of other Allied forces in a Pacific invasion would have been limited — Great Britain, France, Canada and the Soviet Union had been fighting the war longer than the United States. They had just won, and they were ready to get back to normal life.
American military planners estimated that the invasion of Japan would "functionally be a duplication of the casualty surge in Europe," Giangreco explains. And that was "not a pleasant prospect."
American war planners projected that a land invasion of Japan could cost the lives of up to a million U.S. soldiers and many more Japanese. These figures, Giangreco explains, were estimated based on terrain, the number of units fielded, and the number of enemy units they would have to fight.
"Around 1944," Giangreco says, "they ultimately came to the conclusion that the casualties on the low end would be somewhere around the neighborhood of a quarter-million, and on the upper end, in through the million range."
The Difference Between Defeat And Surrender
The invasions and battles at Okinawa and Iwo Jima were ruinous for the Japanese, but Giangreco describes how the Americans and the Japanese derived completely different conclusions from the same conflicts. The Americans extrapolated that the battles were bloody and costly — but in the end it was worth it because they thought the Japanese understood that the U.S. would prevail. The Japanese looked at those same casualties and felt the loss of life was worth it because it sent a message to the Americans that the Japanese were prepared to suffer casualties at a rate the Americans were not.
Some historians argue that Japan was already essentially defeated in 1945, even if it didn't know that. Giangreco says there is a lot to that argument but that "defeat and surrender are two very different things."
Giangreco suspects it would have been much harder to convince the Japanese to surrender than it was to convince the Germans.
"The Germans at least surrendered in very large numbers when they saw a hopeless situation," he says. The only time large numbers of Japanese troops laid down their arms was in Manchuria, when Emperor Hirohito ordered them to surrender.
'I Was Terrified At What Might Happen.'
The appendix of Hell To Pay includes a 1995 letter written by Tales of the South Pacific author James Michener. He refused to allow the letter to be released until after his death. Originally from a Quaker background, Michener was a man of peace, but he stated that he could see no other alternative to the end of World War II.
"I know that if I went public with my views, I would be condemned and ridiculed," Michener wrote. "But I stood there on the lip of the pulsating volcano, and I know that I was terrified at what might happen and damned relieved when the invasion became unnecessary. I accept the military estimates that at least 1 million lives were saved, and mine could have been one of them."
Giangreco says that many Americans and Japanese lives were saved by avoiding a land invasion of Japan.
"It's astounding," he says. "While we were looking at some of our own casualty estimates, the Japanese military was doing much the same thing, and the figure of 20 million appears again and again."
Giangreco says just the number "20 million" is horrific — but he is most stunned by the casualness with which it was used by Japanese military leaders who felt that the loss of life was worth it.