Although that combined they make a pretty formidable enemy, I don't think they are technologically up to speed to take on the US, but they will be soon (Thanks Al Gore and Clinton you commie fuxtix!)
If it came to a war with those countries allied together, it would be a short and quick nuclear battle. The instant they made the first move we would annihilate them, it would be the only way. I think that England and Israel would be on our side. England is a strong ally and Isreal will jump on the opportunity to get rid of Iran and whatever nations jump to her aide in the Mid East.
I think that this current President would certainly let them know prior to any acts of war that the US would use Nukes in defense of its territory and citizens and as an offensive weapon if we felt threatened. That is why I voted for him.