Ralph Austin Bard (July 29, 1884 – April 1975) was a Chicago financier and Princeton University graduate (Class of 1906) who served as Assistant Secretary of the Navy, 1941–1944, and as Under Secretary, 1944–1945. He was one of eight members of the Interim Committee appointed to advise President Harry S. Truman on the use of the atomic bomb. Although Bard joined in the committee's unanimous recommendation that the bomb should be used as soon as possible and without warning against a civilian target in Japan, he developed second thoughts. In a famous memorandum dated June 27, 1945, to Secretary of War Henry L. Stimson, Bard argued that Japan should receive two or three days' "preliminary warning" before the bomb was used. "The position of the United States as a great humanitarian nation and the fair play attitude of our people generally is responsible in the main for this feeling," Bard wrote, adding that he felt "that the Japanese government may be searching for some opportunity which they could use as a medium of surrender."
On August 6, 1945, an atomic bomb was dropped on the Japanese city of Hiroshima without the warning that Bard recommended. On August 8, the Soviet Union declared war on Japan. On August 9, a second bomb was used on the city of Nagasaki. On August 14, Japan surrendered.