The decision by President Obama not to launch air strikes on Syrian government forces after the apparent use of chemical weapons by them on 21 August prepared the ground for a possible US-Iranian deal on Iran's nuclear programme. By its actions, the US showed it was not prepared to undertake military action to overthrow President Bashar al-Assad, Iran's one crucial ally in the Arab world. The US-led assault on Syria was more or less openly directed against Iran, so its abandonment was a decisive turnaround in the 30-year confrontation between the US and Iran. And the fact that this was not simply a zigzag in US policy was born out by popular and congressional hostility towards American involvement in another war in the region.
Iranian officials had long described the threat to the regime in Damascus by the US and its allies as directed in large part at their own government in Tehran. Not only would they have lost an allied state, but Hezbollah would have been isolated in Lebanon if a post-Assad Syria were ruled by a Sunni regime supported by the US, Saudi Arabia and Turkey. The solid band of Shia-controlled or influenced countries, stretching from Iran's border with Afghanistan through Iraq and Syria to Lebanon's coastline on the Mediterranean, would have been broken up. The Sunni counteroffensive against the Shia would have won its first real victory.
The deal between Iran and the US and its allies being negotiated in Geneva this weekend is usually analysed in terms of the likelihood of success and identifying which side is giving the most concessions. The answer to the question about who comes out ahead – contrary to what the Israeli Prime Minister Benjamin Netanyahu has been saying – is that Iran is, for the moment, doing most of the conceding on its nuclear programme, and not getting much back in terms of a relaxation of the economic blockade. Core sanctions on Iran remain, and bankers throughout the world will stay scared of inviting legal retribution from Washington if they have any dealings with Iran.
In return, the Iranians are offering concrete concessions, notably putting an end for the moment to the production of highly enriched, 20 per cent uranium, and stopping construction work at its heavy-water reactor at Arak. This is being done to establish "trust", but does not leave Iran with many assets to negotiate with in future talks over a long-term solution. The danger from Iran's point of view is that the West will gobble up concessions made in the name of "confidence-building", but there will be no stage-two negotiations in which Iran might get something back in return. Sanctions will largely stay in place.
But the less concrete gains by the Iranians are impressive. Since the election as Iranian President of conciliatory Hassan Rouhani this summer, Iran is no longer so easy to demonise as it was under his predecessor, Mahmoud Ahmadinejad, whose blood-curdling rhetoric was an Israeli propagandist's dream come true. Indeed, Israeli journalist Uri Avnery argued that if one looked simply at damage to Iran and benefits to Israel done by Ahmadinejad, then one would rapidly be convinced that the Iranian president was an Israeli agent.
But history will be complicated to reverse. Sanctions on Iran may be difficult to modify because they were put in place by Congress as instruments of its own anti-Iranian policy. One reason why the White House wants to negotiate with Iran now is to stop Congress from passing a fresh round of sanctions. On the other hand, the Israeli Finance Minister Yair Lapid was arguing that once the political tide behind sanctions started to ebb they would be swept away willy-nilly, because international businesses were queuing up to get into Iran. It might be good if this were true, though the forces against an accommodation with Iran are impressively powerful: Israel, Saudi Arabia and the Gulf monarchies abroad, much of Congress at home.
Opponents of a deal with Iran argue that because sanctions have achieved much in terms of damaging its economy, they can do everything. They do not notice or, if they do, are careful not to draw attention to the fact that, effective though economic sanctions may be in their impact on Iranian's living standards, their effect on Iran's nuclear programme has been to speed it up.
Pressure on the West for a deal with Iran sooner rather than later stems from the fact that diplomats say Iran may be in a position to test a nuclear weapon by next summer. This is not to say that sanctions do not have a devastating effect, but not enough for the Iranians to run up the white flag. The Iranian government will also be in a stronger political position at home if it is seen by its own people to have sought an international agreement on its nuclear programme and to have been rebuffed.
The US congressional opponents of a deal with Iran always behave as if the US has more cards in its hand than it has in reality. Iran is stronger than it was 12 years ago, when its neighbours included a hostile and fanatically Sunni Taliban regime to the east in Afghanistan and an equally hostile Saddam Hussein to the west. In Iraq, Iran is the predominant power, and in Syria, Assad is more dependent on Iran then ever before. The US has fought two wars in Iraq and Afghanistan in the past decade in which it wholly failed to achieve its aims. Belligerent rhetoric from William Hague about military action against Iran or Syria is not going to frighten anybody – if it ever did – after Parliament voted against it.
Could Israel go it alone? Israel does not generally go to war without some sort of green light from Washington. The Israeli military threat against Iran has always seemed to be the bluff of the century, but a highly effective bluff which induced the rest of the world to impose more severe sanctions than Iran expected.
The US has been engaged in a cold and hot war against Iran since the fall of the Shah in 1979. Could this rivalry be coming to an end? This is unlikely to happen overnight, but the confrontation might be taking a more benign form.