I've read this phrase one thousand times in the recent weeks. It implies that though the administration is apparently committed to diplomacy, it doesn't exclude the possibility of military action and, moreover, is preparing one behind the scenes...
And you know what? I don't believe it.
There is absolutely no historical evidence to support such a suggestion.
What is even more important, how do you prepare a military action against a huge country like Iran in that perfectly stealth way?
So when the sh*t hits the fan, it will be ad hoc messy operation, if any. Israel is alone in this, and she better do something now...
What's messy about a smooth surface of freshly-formed glass where a desert used to be??