That letter senate republicans sent to iran so far causing nothing but trouble. secretary of state john kerry laying into senators saying the letter left him quote in utter disbelief. meanwhile, negotiations with iran are still under way and the real fear is that the letter could make matters worse, let's discuss if that's true. hilary nall levertt tlor of "going to iran" and a former clinton and bush national security adviser and we have peter beinart, contributing editor "track media" and a senior fellow at the new america foundation. can you make the case to me about why this letter was hel...