If Iran pushes the button, Iran is toast.
They will get paid back ten fold what they dish out.
I think they know it, but I also think they are also crazy enough to do it. They are backed into a corner, like a rabid dog, and will bite soon.
Not to be contrary, but it appears to me that Israel is the one backed into a corner. Iran seems to have most of the world's support. They're livin' large, so I don't see any urgency in them attacking Israel at this point. They CERTAINLY won't attack Israel before they actually have a nuclear weapon. I can't imagine they'd come all this way to launch a conventional attack and see their country turned into Swiss cheese. And even if they have a weapon, how will they deliver it? They can't just fuel a rocket like they're at the self-service pump. We would see it days ahead of time.
Anyhow, I think we're in for some kind of massive terrorist attack in the Middle East. The Saudis busted up a cell of terrorists yesterday. I don't expect anything in the United States. Busting the liquid bomb project probably disrupted and compromised anything else they may have had planned in the Western Hemisphere.