Gen. Dwight Eisenhower stated in his memoirs that when notified by Secretary of War Henry Stimson of the decision to use atomic weapons, he “voiced to him my grave misgivings, first on the basis of my belief that Japan was already defeated and that dropping the bomb was completely unnecessary, and secondly because I thought that our country should avoid shocking world opinion by the use of a weapon whose employment was, I thought, no longer mandatory as a measure to save American lives.” He later publicly declared, “It wasn’t necessary to hit them with that awful thing.”
Even the famous hawk Maj. Gen. Curtis LeMay, the head of the Twenty-First Bomber Command, went public the month after the bombing, telling the press that “the atomic bomb had nothing to do with the end of the war at all.”
Fleet Adm. Chester Nimitz, the commander in chief of the Pacific Fleet, stated in a public address at the Washington Monument two months after the bombings that “the atomic bomb played no decisive part, from a purely military standpoint, in the defeat of Japan.”
Adm. William “Bull” Halsey Jr., the commander of the US Third Fleet, stated publicly in 1946 that “the first atomic bomb was an unnecessary experiment…. It was a mistake to ever drop it…. [The scientists] had this toy, and they wanted to try it out, so they dropped it…”
“It was a mistake.... [the scientists] had this toy and they wanted to try it out, so they dropped it.” —Adm. William “Bull” Halsey
The commanding general of the US Army Air Forces, Henry “Hap” Arnold, gave a strong indication of his views in a public statement 11 days after Hiroshima was attacked. Asked on August 17 by a New York Times reporter whether the atomic bomb caused Japan to surrender, Arnold said that “the Japanese position was hopeless even before the first atomic bomb fell, because the Japanese had lost control of their own air.”
“The use of this barbarous weapon…was of no material assistance in our war against Japan.” —Adm. William Leahy, Truman's Chief of Staff