Sam Roggeveen runs down the scenarios:
My logic is simple. With regard to Iran's nuclear program, Israel faces one of three possible futures:
1. Israel has nuclear weapons but Iran does not.
2. Both Israel and Iran have nuclear weapons.
3. Neither Israel or Iran has nuclear weapons.
Which scenario is better for Israel's security?
Roggeveen concludes that option one is probably unsustainable and option two undesirable, which leaves option three as the best course. Moreover, it would put Israel in a better position because of its superior conventional military.
My guess: we're heading toward option two. No country with an arsenal as well developed as Israel's has ever completely abandoned nuclear weapons, the regional environment isn't exactly reassuring for Israel to do so in the first place and Iran would be foolish (from their own perspective) to live with such a huge conventional imbalance if the nuclear option was within reach.