At what point, if any, would Obama be willing to abandon diplomacy and launch airstrikes against Iran's nuclear facilities (or give a wink to Israel to do so)? And what is the point, if any, at which Hillary would be willing to do the same? And what is the difference, if any, between those two points? (Obama has called an Iranian nuke "unacceptable," and I think Hillary used the same word.) And: Is this something they've discussed?

--Michael Crowley