The content originally appeared on: CNN (CNN)An effort to save the Iran nuclear deal appeared to hang in the balance on Thursday after Washington said Tehran's latest reply to the European Union proposal was 'not constructive.' A US State Department spokesperson said the United States had received Iran's response to the EU bid to revive the 2015 deal and would formulate its own response. 'We are studying it and will respond through the EU, but unfortunately it is not constructive,' […]