Putting aside the very real issue of whether the Iranian leadership would ultimately agree to a nuclear deal to end the sanctions, an even bigger hurdle is whether the U.S. Congress would ever agree to lift them if such a deal ever does happen. I think the chances of that are practically nil, even if Iran agrees to everything the U.S. wants. The bottom line is that Iran has been so thoroughly demonized to the American public for the past 35 years, it would be political poison for an American politician to publicly agree to ease up on Tehran.