It is unclear how this development changed the tone of the closed-door meetings. Furthermore, Iranian officials have simultaneously expressed optimism about the prospects for a final deal and irritation at the latest US measures and at Western negotiators’ refusal to fully accept Iranian positions. Thus, it remains to be seen whether any real progress can be expected at the next round of negotiations, scheduled for September 18.

Also complicating the prospect of a deal is the ongoing, separate inquiry into Iran’s past nuclear activities, which is being conducted by the UN’s International Atomic Energy Agency. It has already been reported that Iran failed to provide promised transparency measures in time to meet an August 25 deadline. In light of this and other obstacles to the process, it is expected that the IAEA will shortly issue a report declaring that little progress has been made.

Despite the fact that the IAEA inquiry is separate from the P5+1 talks, if this situation continues, the US and its allies are very likely to conclude that Iran is neither committed to the process nor sincere about giving up on its nuclear weapons ambitions.