How much rope will Iran’s regime give Rouhani?
Perhaps not since 2003’s acrimonious arguments about Iraq has the United Nations felt quite so important as it does now.
Aside from the prospect of the first UN resolution on Syria disarming its chemical weapons, we have an American president speaking this morning, and a new Iranian president doing the same in this afternoon, and the possibility that both men will meet in the UN building at some point.
Not since the last Shah met Jimmy Carter in the late 1970s has such a high-level meeting taken place.
Since Iran’s 1979 Islamic revolution and the parading of blindfolded American hostages, the Americans have placed their regional eggs in the Gulf Arab basket, arguably without much success: none of the 9/11 hijackers were Iranians, but 15 of them were from Saudi Arabia.
Whatever the dire human rights abuses perpetrated by the Iranian regime over three decades, it is surely about time America looked at the Sunni-Shia world with a more balanced perspective.
Read more: Iran does ‘not seek war with any country’, pledges Rouhani
Diplomacy is definitely the order of the day, but if some of the prospects sound too good to be true, they probably are.
Maybe the US secretary of state will meet President Hassan Rouhani and Barack Obama will not – the thinking being that Iran has to take “concrete steps” before any presidential encounter can take place.
Mr Obama reached out to the Iranians during his first term and got nowhere.
“Concrete steps” was the phrase used by Britain’s Foreign Secretary yesterday.
When I asked William Hague if he shared the optimistic view that this was the best chance of rapprochement with Iran in 34 years, he was far too cautious to say yes.
Mr Hague also declined to address my question as to whether the UN Security Council’s long held demand that Iran suspend uranium enrichment was still the precursor to any deal with the Iranians.
Clearly everything is up for grabs here and no one knows the chances of success.
Read more: What have we learnt about Iran’s Hassan Rouhani?
The British embassy in Tehran was ransacked in 2011 and a guarantee that it can reopen safely will be the UK’s desired first “concrete step”.
The risk for the British and other Europeans is that the Iranians insist on dealing with America direct and attempt to scrap the current nuclear negotiating process, cutting everyone else out of the picture.
At least initially, any substantial movement by the Iranians will probably require direct American input: John Kerry will meet Javad Zarif, his Iranian counterpart, for the first time on Thursday.
The risk for the Americans is that President Obama demands too much from Iran in terms of more UN inspections or immediate suspension of uranium enrichment.
The president has already surrendered a decision on bombing Syria to a vote on congress; congress will also want a say in setting touch terms for Iran, with the Israel lobby already hitting the telephones to Capitol Hill, warning senators and congressmen not to go soft on the Iranians.
As Israel’s Prime Minister Benjamin Netanyahu put it in a recent statement,”the Iranians are engaged in a media spin to keep the centrifuges spinning”.
Read more: Iran’s Rouhani wants talks, not threats, on nuclear issue
And if the Iranians sense too much US-Israeli pressure without the prospect of sanctions relief in sight, they may walk away from talks.
How much rope will the Iranian regime give President Rouhani before more hard line elements pull him back and say, “there, I told you so, we can never trust the Americans”?
Iran is clearly showing willing, with prisoner releases last week and yesterday.
Whether it will agree to close a small nuclear plant at Fordow, or allow an old explosives-testing site at Parchin to be inspected, we don’t yet know.
However far the Iranians go, they will be hoping for a rapid response to show those hard liners in the Revolutionary Guard and elsewhere that diplomacy really does work.
Follow @jrug on Twitter