While Obama and Panetta have used brash rhetoric to say they will not allow Iran to field an atomic weapon, Cartwright said it is unclear whether those vows have real-world muscle.
"Several presidents now have said, 'Not on my watch. No way will we ever allow that to happen," Cartwright said. "What does that mean? We said that about [North] Korea, too."
As Washington seeks ever-tougher sanctions and Israel continues pounding its war drums about a strike this summer, Cartwright predicted global political dynamics will prevent a strike this year. "The likelihood that that's going to occur in a year when you're going to get a new Chinese government, a new French government, a new U.K. government," and possibly a new U.S. president, "stacks up pretty hard against kinetic action."
Some in Washington have begun debating whether a nuclear-armed Iran could be contained. Panetta has rejected the notion, but Fallon suggested it just might work.
"If [Iran] gets the capability, they're going to be in a box," Fallon said, because "if they ever try to use this, it's game over for them very quickly."