Franklin Roosevelt had never told his vice president, Harry Truman, about the Manhattan Project or the unusual weapon that it was developing. When Roosevelt died unexpectedly, on April 12, 1945, Truman had the thankless task of replacing a beloved and charismatic leader during wartime. The new president was unlikely to reverse a nuclear policy set in motion years earlier, at enormous expense, because a group of relatively unknown scientists now considered it a bad idea.
