The most significant diplomacy surrounding the opening of this year’s UN General Assembly did not involve Syria but Iran. What was agreed with Tehran is potentially significant. Talks will focus on nuclear issues. The rationale was straightforward: if nuclear talks succeed, everything else is possible; if no nuclear deal is reached, nothing else will matter.
Once there is agreement on an end-game, the sides will negotiate the pace and sequencing for getting there. Thus implementation will be step by step, but the parties will know what the final step will require before they take the first one.