Neither the US nor Israel can really attack Iran. Russia and China probably already threatened to nuke Israel if they do so. It's probably part of a bigger deal like Russia promessed not to deliver the S300 missiles to Iran, etc...
Iran will have nuclear weapons but even if M.A. is a clown, Iran being a tri-millenar culture, they will never use them offensively.
In fact, the US might be actively monitoring Israel about it.