President Barack Obama faces an almost impossible balancing act between making overtures to Iran that will allow it to pursue its nuclear programme for energy purposes, and appeasing the security fears of Sunni Arab leaders.
On the table in American-Iranian talks is the prospect that the latter will be allowed to keep 5,000 centrifuges, used to enrich uranium, and a growing research and development operation.
But tensions over the US’s thawing policy towards Tehran will loom large over the meetings, already threatened by the decision of key states to send lower-level dignitaries.