When the world’s major powers struck a deal over Iran’s nuclear program in Vienna in July, it represented a victory not just for the Islamic Republic, which has now been granted international legitimacy as a nuclear threshold state, but also for a small but increasingly influential lobby in America, one which has long sought rapprochement between Washington and Tehran and now seeks to leverage a successfully concluded nuclear deal as a means to that end. This Iran lobby, publicly represented by the National Iranian American Council (NIAC), has become a staunch institutional ally of the White House selling the Joint...