Cyber War! FRONTLINE

Cyber War In the aftermath of Sept. 11, 2001, as most U.S. intelligence shifted to finding Al Qaeda cells around the world, one group at the White House decided to investigate a new threat -- attacks from cyberspace. "In the past, you would count the number of bombers and the number of tanks your enemy had. In the case of cyber war, you really can't tell whether the enemy has good weapons until the enemy uses them," says Richard Clarke, former chairman of the White House Critical Infrastructure Protection Board. In "Cyber War!" Clarke and other insiders talk about a new set of warriors fighting on the new battlefield of cyberspace, and they evaluate just how vulnerable the Internet may be to both virtual and physical attack.