Fat Man

Fat Man was the plutonium atomic bomb dropped on Nagasaki on August 9, 1945, and the second atomic bomb used against Japan. Its arrival was governed by an earlier military directive: the weapon was sent from Tinian as soon as the project staff had made it ready, without a new high-level meeting or an additional decision by Harry S. Truman. Its history therefore turns on both its destructive force and the administrative process that put it into use.

Identity and authorization

Fat Man was a plutonium bomb, nicknamed while it was being prepared for use. The order governing its deployment had been sent on July 25 by General Thomas T. Handy, deputy to General George C. Marshall, to General Carl A. Spaatz of the Twentieth Air Force. Its second paragraph provided: “Additional bombs will be delivered on the above targets as soon as made ready by the project staff….”

Delivery and use

Once Fat Man was ready, it was “delivered” from Tinian. The delivery took place two days ahead of schedule in view of weather conditions. No high-level meeting had been held about this second bomb, and Truman had made no further decision; there was no additional order beyond the July 25 directive. The distinction is consequential: the weapon’s use followed a standing instruction rather than a separately recorded presidential authorization for this particular bomb.

Destruction and aftermath

Later estimates put the number killed at Nagasaki at seventy thousand. The destruction would have been worse had the bombardier not missed the target by two miles. The estimate and the miss register two different dimensions of the bombing: the immense human cost, and the role that the weapon’s actual delivery—not merely the decision and directive behind it—played in determining the damage.