[...] In the twentieth century terrorism became, largely through the innovations of aerial bombardment by airplane and guided missile, the principal means by which states waged war. Hiroshima is, in that way, the century’s hinge. It was a straightforward terrorist attack on the civilian population of two Japanese cities, designed to break the will to fight of the Japanese government. In that one way it is not different in kind from the stateless terrorism practiced by al-Qaeda or the insurgent Sunni rebellion in Iraq. [...]