The second atomic strike on the city of Nagasaki is less well known than the one a few days earlier on Hiroshima, but was it more influential in forcing the Japanese to surrender? To find out who exactly ordered it and why Dan talked to Harvard's Frederik Logevall. He discusses the debates that rage between historians as to whether Nagasaki was necessary and how much pressure there was for a third bomb. On the anniversary of the strike, it is a conversation with powerful contemporary echoes.