"Why We Did It!"

     Truman wasn't fully briefed on the atom bomb for another two weeks.  Then he was lectured, somewhat impatiently, by General Leslie R. Groves, the man in charge of the Manhattan Project, the all-out top-secret effort to build the atom bomb.  In Groves' mind, Truman's only job was to acquiesce.  The new president went along for the ride, Groves later boasted, "like a little boy on a toboggan."  Such hubris was characteristic of Groves, a three-star general who earlier had made his reputation building the Pentagon. 

     Outwardly confident, somewhat overweight from compulsively munching chocolates, Groves would keep senior officials waiting outside his office for an hour.  Then he would poke his head out and demand, "What are you doing here?"  The so-called Atom General had almost 200,000 people working on the project at 37 secret plants and laboratories, and only a few knew what they were really working on.  Groves prided himself on his ability to manipulate.  Noticing that Truman had faithfully hung a portrait of FDR on his wall ("I'm trying to do what he would like," said Truman), Groves played on his insecurities.  If the A-bomb project came to naught, Groves told Truman, it would "cast  a lot of reflection on Mr. Roosevelt."

     For all his cockiness, Groves was worried that his bomb would be a dud.  Others in the military were skeptical about a mystery weapon purported to unlock the power of the universe.  "The damn thing" will never work, said Adm. William Leahy, the chief of staff at the White House and an old "ordnance man" in the navy.  Groves had spent $2 billion ($26 billion in today's dollars) on the project.  Failure, he knew, would not only make FDR look bad.  It would result in "the greatest congressional investigation of all times" - with General Groves in the dock.

     The scientists working on the bomb at the Manhattan Project's top-secret laboratories in the New Mexico desert were confident that they could make a big bang - but they weren't sure how big.  More cautious military planners argued that the bomb would have to be followed up by a raid of B-29's dropping incendiary bombs to guarantee a large conflagration.  The planners did not think the bomb would be big enough to end the war in one blow.

     Groves was determined to demonstrate the power of what he called "the gadget."  But by the late spring of 1945 he was running out of good targets.  Gen. Curtis LeMay of the 20th Air Force was methodically destroying the cities of Japan with numerous firebombing raids.  During 10 days in March, 11,600 B-29 sorties had wiped out 32 square miles of the four largest Japanese cities, killing more than 150,000 people.  A raid on Tokyo on May 25 created a gigantic firestorm; bomber crews in the last waves could smell burning flesh thousands of feet below.  Reading the bomb-damage assessments, Groves worried that he would not be able to find a city sufficiently unsullied to serve as a proper showcase for his new terror weapon.

     Hiroshima, a city of 280,000 people at the southern end of Honshu, the largest of the Japanese islands, was a possibility.  According to a report prepared by Groves' staff, the city was surrounded by hills that would "produce a focusing effect which would considerably increase the blast damage."  But, crisscrossed by rivers, Hiroshima was not the best candidate for a firestorm.  A better target, Groves believed, was Kyoto.  The ancient capital with its Buddhist and Shinto shrines, had been spared so far.  Groves liked the fact that the city was an "intellectual center."  The victims would be "more apt to appreciate the significance" of the bomb.

Please read on...