"The lessons learned with the failure to find the weapons of mass destruction, and some of the other things that happened, will make any future president very, very cautious about launching that kind of conflict or relying on intelligence," [Robert Gates] said.

He added, "I think that the barrier, first of all, will be, 'Are we going to be attacked here at home?'"

"They're not close to a stockpile, they're not close to a weapon at this point, and so there is some time," Gates told NBC's Meet the Press when asked whether the Islamic republic could be deterred from pursuing nuclear weapons.