An extraordinary flurry of reports erupted last week over intercepted secret messages between the Pakistani al-Qaeda chief Ayman al-Zawahiri and his deputy in Yemen about plans for a major terror attack. The information triggered the shutdown of 19 US embassies across the world. But hidden between the lines of stories by virtually all of the US's top news media was the question of how the story got out, and who was authorized to leak to whom -- with apparent impunity.