Islamic extremism is the gravest threat to U.S. security / George W. Bush -- Terrorism, not Islamic extremism, is the true threat to U.S. security / Shibley Telhami -- Iran is not a threat to U.S. national security / Scott Ritter -- Threats to U.S. energy security jeopardize national security / Barack Obama -- U.S. energy security is not threatened / Eric Gholz and Daryl G. Press -- Homeland security is working / Michael Chertoff -- Homeland security is a failure / Joan Claybrook -- The Protect America Act is necessary to thwart terrorism / Kenneth L. Wainstein -- The Protect America Act is a threat to civil liberties / Aziz Huq -- Cyberterrorism is a growing threat to U.S. security / Keith Lourdeau -- The U.S. needs sound fiscal policy to avoid jeopardizing national security / Robert Hormats.