It's WWIII which will inevitably start. Attacking Iran's nuclear sites is absolutely not the same as what Israel did in Iraq or Syria. Iran has an army. An excellent one. They are constantly training and also receiving support from Russia. They have a rule not to attack unless they are attacked. If they are attacked there won't be a state for the Palestinians to claim let alone the Israelis.
U.S. says working on initiative to de-escalate Syria fighting, with focus on Aleppo (Reuters)
from the article: Obama's new security staff may approve attack on Iran