Well I know our problems with Iran go back at least to 1979 when they took over our embassy there and held about 50 Americans hostage for a year. They have been threatening to "wipe Israel off the map" for years and we believe are developing nuclear weapons and missiles to do just that. And they have threaten to shut down the Persian Gulf blocking our oil supplies. So it's not like they have have been friends to the US or that we don't have good reason to be wary of them.
As I have said here many times- the whole Middle-East is a powder keg of religious extremist nuts who will eventually trigger a nuclear war and I wish the US had nothing whatsoever to do with anyone in that part of the world. Unfortunately our need for oil and commitments to Israel makes that impossible. I think we should do whatever it takes to end our foreign oil dependance and get completely out of this area- but that still leaves the matter of Israel, whom the US seems obligated to protect. I'll let Bob explain that.