What were the two reasons President Eisenhower thought the bombs were unnecessary? How did its use affect him?

On 26 July 1945, United States President Harry S. Truman, British Prime Minister Winston Churchill and President of China Chiang Kai-shek issued the Potsdam Declaration, which outlined the terms of surrender for the Empire of Japan as agreed upon at the Potsdam Conference. This ultimatum stated if Japan did not surrender, it would face "prompt and utter destruction".[1] Some debaters focus on the presidential decision-making process, and others on whether or not the bombings were the proximate cause of Japanese surrender.

Over the course of time, different arguments have gained and lost support as new evidence has become available and as new studies have been completed. A primary and continuing focus has been on the role of the bombings in Japan's surrender and the U.S.'s justification for them based upon the premise that the bombings precipitated the surrender. This remains the subject of both scholarly and popular debate. In 2005, in an overview of historiography about the matter, J. Samuel Walker wrote, "the controversy over the use of the bomb seems certain to continue".[2] Walker stated, "The fundamental issue that has divided scholars over a period of nearly four decades is whether the use of the bomb was necessary to achieve victory in the war in the Pacific on terms satisfactory to the United States."[2]

Supporters of the bombings generally assert that they caused the Japanese surrender, preventing massive casualties on both sides in the planned invasion of Japan: Kyūshū was to be invaded in November 1945 and Honshū four months later. It was thought Japan would not surrender unless there was an overwhelming demonstration of destructive capability. Those who oppose the bombings argue it was militarily unnecessary,[3] inherently immoral, a war crime, or a form of state terrorism.[4] Critics believe a naval blockade and conventional bombings would have forced Japan to surrender unconditionally.[5] Some critics believe Japan was more motivated to surrender by the Soviet Union's invasion of Manchuria and other Japanese-held areas.[

i see, would you mind putting it as one?