Fewer than 1 in 25 Americans alive today have even the faintest memory of World War II. Pearl Harbor, the draft, D-Day, Iwo Jima — they are all simply material in history books to about 10 million to 15 million Americans. The same is true for the final moments of the war: the United States ending the war by dropping atomic bombs on the Japanese cities of Hiroshima and Nagasaki in August 1945.

As the 75th anniversary of that bombing passed, debate over the atomic bomb flared up. Did President Harry Truman make the right call? What was the alternative? Was it any worse than our “conventional” bombing of Tokyo or German cities?