the 5+1 demand that Iran abandon all her nuclear enrichment activities, which Iran can do based on her NPT membership. That illegal demand by a few Iran's enemies has not been dropped from the UNSC resolutions. So it seems to me the 5+1 must officially recognize Iran's right to enrich Uranium for peaceful and power generation purposes. Are you aware of such official announcement?
NYT: U.S. Vice President Joe Biden considering run for 2016 presidency (Reuters)
from the article: ANALYSIS / Iran trying to maintain momentum of dialogue