https://thefederalist.com/2020/08/06/75-years-later-its-clear-truman-was-rig
Ultimately, the decision to use atomic weapons against Japan hastened the end to WWII, halted further Soviet aggression, and saved millions of lives.
On August 6, 1945, 30-year-old U.S. Air Force pilot Col. Paul W. Tibbets Jr. took to the sky in the Enola Gay, his Boeing B-29 Superfortress heavy bomber. His destination, the Japanese city of Hiroshima, was not an especially notable target. His payload, however, a single bomb nicknamed “Little Boy,” would change the course of history.
True watershed moments in history are rare — the agricultural revolution is one such example, as was the Battle of Salamis, the advent of Jesus Christ, and the fall of Western Rome. Yet in the last 1,500 years, no two distinct epochs of time are as clear as the time before the atomic bombings of Hiroshima and Nagasaki and all the time since.
‘Prompt and Utter Destruction’
Eleven days before Tibbets’s fateful flight, on July 26, 1945, U.S. President Harry S. Truman’s “Potsdam Declaration” gave the Empire of Japan one final chance to surrender unconditionally after more than three years of war in the Pacific. If they persisted in fighting, the Potsdam text promised “the full application” of U.S. military power, culminating in “the inevitable and complete destruction of the Japanese armed forces and just as inevitably the utter devastation of the Japanese homeland.” The closing of the ultimatum rings all the more forebodingly in hindsight: if the Japanese refused the terms, the alternative was “prompt and utter destruction.”