What can be more chilling than the statistics of war? Tens of thousands dying in a single day on the Western Front in World War I. Millions perishing in World War II. India. Pakistan. Korea. Kenya. Vietnam. Cambodia. Rwanda. Iraq. And where next?

Among all this immense bloodletting, one instance of human cruelty stands out as a portent of our future.

At approximately 8:15 on the morning of Monday, Aug. 6, 1945, the world's first atomic-bomb attack was carried out on the city of Hiroshima in western Japan. U.S. President Harry Truman, addressing his nation and the world on Aug. 9, called Hiroshima "a military base." The bomb was used, he said, "to shorten the agony of war."