1. Attack Iran. 2. Do not attack. It really comes down to a choice of evils. But I think a multi-national/NATO response would be better than if Israel attacked alone. It would be better for Israel if Israel did not have to do the attacking. After all, a nuclear armed Iran threatens the stability of the entire region.
U.S. says working on initiative to de-escalate Syria fighting, with focus on Aleppo (Reuters)
from the article: Mossad chief: Nuclear Iran not necessarily existential threat to Israel