There's been a significant amount of activity on three different fronts in recent days. Progress on each is nascent and fragile - but taken together also quite important.

Brief thoughts on the state of play [thread]:

2/ The main story has been in Vienna, where 2 rounds of expert-level talks will pick up next week. Fact that a third working group has been set up on sequencing suggests sufficient progress on the nuke/sanctions working groups to start thinking of how steps should be implemented.

3/ Rouhani has suggested that discussions are at 60-70%, others say halfway, DC says long way to go.

I wouldn't read too much into this. Even if we're at 99%, that last 1% can undo all the rest of it. Need to be sober on prospects, mindful of pitfalls.

4/ Indeed, pitfalls become more acute the more progress is made: whether principals sign off to what negotiators are discussing; how domestic audiences react; how outside spoilers respond. Natanz explosion showed how already-delicate dance can encounter broken glass.

5/ 2nd track sees Iran & the IAEA resuming discussing on clarifying safeguards concerns. This has been a dogged source of friction, and as @CrisisGroup has consistently argued, requires constructive Iranian engagement with the agency.

6/ 3rd track is Saudi-Iranian talks that have now been confirmed by multiple sources. Two points of interest here: a) discussions are being conducted by intel/SNSC, which will be esp important to Riyadh due to key role of security officials in Iran's regional policy.

7/ b) Focus has reportedly been on de-escalation in Yemen, and conversations apparently set to continue in coming weeks. Difficult to overstate importance of regional actors engaging directly on regional issues, and breaking zero-sum dynamics that benefit neither side.

8/8 Restoring JCPOA, resolving IAEA concerns, re-engagement between KSA & Iran each a complicated set of challenges; traction on any/all as likely to falter as succeed. But odds of success are nil without trying.