Look, I'm not an Iran fan. However, our involvement with the Shah and our subsequent poor diplomatic efforts don';t earn us a gold medal either.
One thing I've learned through life is that being "right" is not always as valuable as being "smart".
Lets say we approached Iran and said "look, we're sorry for pissing you off. We feel we may have done the wrong thing. We'd like to try to start over with a clean slate. We have a lot to offer you and if you'll hold off on your bomb-biz for 3 years, we'll trade with you, tour you, exchange education with you and help you develop nuclear plants if you want us to. All we ask is to give all this another try.Not only that, but we'll throw some money at the Palestinians and we'll tell Israel that building one more ****ing settlement will cost them their foreign aid."
So, maybe it works - yowser. Maybe they tell us to **** off - hey, we really tried. It's LOGICAL to try to avoid killing 10s of thousands of people, isn't it?
So, maybe you say "sure Mr. Logical, and what if they say yes but they sneak around and build a nuke?". Well, it's not as if we don't have about 3,000 nukes ourselves and we'll be incapable of defending ourselves.
Just a speculative opinion of course.....