
After the bombing of Hiroshima and the Russian declaration of war, Japanese leaders decided to sue for peace. Advocates of surrender needed only enough time to work out acceptable terms and to reconcile military officers to the inevitable. As the Japanese discussed policy, the Americans followed standard military procedure. Control shifted from the commander in Washington, President Truman, to the commander of the bomber squadron on the island of Tinian in the Pacific. Plans called for Fat Man, a plutonium bomb, to be ready by August 11. Since work went faster than expected, the bomb crew advanced the date to the ninth. The forecast called for clear skies on the ninth, followed by five days of bad weather. Urged on by the squadron commander, the crew had Fat Man armed and loaded on the morning of the ninth. And again following military SOP, the pilot shifted his attack to Nagasaki when clouds obscured his primary target.
Had the original plan been followed, Japan might well have surrendered before the weather cleared. Nagasaki would have been spared. But the officer who ordered the attack had little appreciation of the larger military picture that made Nagasaki a target or that made the Soviet Union a diplomatic problem connected with the atom bomb. He weighed factors important to a bomb squadron commander, not to diplomats or political leaders. The bombing of Nagasaki slipped from the hands of policy makers not because of some rogue computer or any power-mad, maniacal general, but simply because of military SOPs.
— James West Davidson & Mark Hamilton Lytle, After the Fact: The Art of Historical Detection, fourth edition (2000)
On August 9, 1945, the bomb named “Fat Man” was dropped on Nagasaki by a USAAF B-29 airplane named “Bockscar”, piloted by U.S. Army Air Force Major Charles Sweeney. Source.


