Americans should be braced for a long battle against the brutal terrorist group Islamic State that will test U.S. resolve — and the leadership of the commander in chief, says Leon Panetta, who headed the CIA and then the Pentagon as Al Qaeda was weakened and Osama bin Laden killed.

"I think we're looking at kind of a 30-year war," he says, one that will have to extend beyond Islamic State to include emerging threats in Nigeria, Somalia, Yemen, Libya and elsewhere.