There's one possibility I haven't seen brought up, what if the B-2s fly over, drop the bunker busters without incident, only to learn that they failed to take out the underground nuclear facilities? At that point, there's not a conventional weapon in America's arsenal that can take them out, leaving Trump with the choice of accepting Iran as a nuclear power or launching a full scale invasion.
Considering how he's acted so far, do you think he doesn't spend the rest of the year mustering desert storm 2.0 to save Israel's pride?