My understanding of the nuclear deal is the US will be committed to defending Iran against Israel. This shortens the Israeli attack timetable to right before the vote. I’m sure Israel has already been threatened by Obama but he’s less likely to act without some paper backing like this nuclear agreement. I’d hate to be the one making this call as Obama is forcing actions that may result sooner or later in casualties on the scale of Dresden. (That Nobel prize will seem especially stupid after this.)