The real threat lies in the proliferation of nukes to proxy terrorist organisations . A nuclear strike by Islamic Jihad or Hezbollah is existential for such a tiny country. Moreover, it does not permit a nuclear response option. There is no reason to assume the Iranian would refrain from supplying those groups. Since is no deterrence in place against nuclear terrorism - any delay to the Iranian programme, be it only for a few year - should justify a pre-emptive strike. A neocon Republican president might be willing to do what Obama does not - a limited ground invasion supported by substantial air cover. So yes - it does make sense to delay the programme only for a few years even if it all it does is buy us more time.
Saudi FM: We hope Iran uses sanction relief for development, not nefarious activities (Reuters)
from the article: Iran expert: U.S. elections increase likelihood of Israeli strike