Scenes from The Accidental President: Harry S. Truman and the Four Months that Changed the World (clockwise from top left): Truman as a young haberdasher, circa 1920. Truman as VP candidate with FDR. Truman's swearing in, following FDR's death on April 12, 1945. Truman meets Winston Churchill for the first time, in Soviet-occupied territory on July 16, 1945. On this same day, the Trinity shot is fired—the first ever atomic explosion, in New Mexico. The nuclear destruction of Nagasaki, on August 9, 1945, less than four months after FDR's death.