Introduction / Strobe Talbott and Nayan Chanda -- And now this : lessons from the old era for the new one / John Lewis Gaddis -- Empowered through violence : the reinventing of Islamic extremism / Abbas Amanat -- Maintaining American power : from injury to recovery / Paul Kennedy -- A Herculean task : the myth and reality of Arab terrorism / Charles Hill -- Clashing civilizations or mad mullahs : the United States between informal and formal empire / Niall Ferguson -- Preserving American values : the challenge at home and abroad / Harold Hongju Koh -- Rethinking the unthinkable : new priorities for new national security / Paul Bracken -- The Challenge to science : how to mobilize American ingenuity / Maxine Singer.