If it were me, in order to do my best to avoid a war, I would tell the world that Israel will have American backing for whatever they need. I think that may make Iran at least know they have NO chance of survival if they don't stop what they are doing.
Weakness will guarantee a war.
I don't see Obama bombing Iran and like the Bush, Obama will not give the Israelis the green light and the Iraq fly over rights needed to attack Iran.
A war the globalist elite badly wants to start. They want to start World War III in the Middle East.