The latter point is no secret to informed observers of the intricacies of Iranian regime politics. Larijani is also secretary of the Supreme National Security Council, and in that role reports directly to Khamenei. The Khamenei-Larijani nexus helps explain Larijani's own request in May 2006 (through diplomatic channels, but heavily leaked) for direct talks with the US; Mahmoud Ahmadinejad's rambling, unworldly public letter to his counterpart George W Bush in the same month is also inconceivable without it.

Indeed, inside Iran there is - notwithstanding the regime's routine double-talk - virtual open house on broaching the once-taboo subject of "normalising" relationships with the US. The visit to Damascus of the speaker of the US House of Representatives, Nancy Pelosi, was followed by speculation that Tehran would be her next destination; the suggestion was met with enthusiastic words of "support" by the first deputy speaker of the majlis (parliament) and head of its main rightwing faction, Mohammad Reza Bahonar.

Old agenda, new champions

For ordinary Iranians, such dramatic U-turns are almost too bizarre for words - especially at a time when journalists have been prosecuted and their newspapers shut down merely for evaluating the state of US-Iran relations. In 2002 three separate Iranian polling institutes - including the National Institute for Research Studies and Opinion Polls (Nirsop) were closed and their researchers imprisoned for revealing that 64.5% of Iranians favoured resumption of talks between Iran and the United States.

Ali Abtahi, Iran's deputy president during the reformist era of Mohammad Khatami's presidency (1997-2005) comments on the current reversals of attitude in a short article titled "As always, if only". He says that "the taboo of dialogue with the US has broken... and everyone is openly racing for US talks, waiting to see what the other side has to say". Abtahi recalls that in 2000, a potential meeting between Khatami and Bill Clinton was choreographed on the fringe of the "millennium summit" of the United Nations; but that "the (Iranian) president did not have the option of talking with an American president, and to escape talks he had to resort to a game of hide-and-seek".

In 2000, the power of the conservatives opposed to Khatami blocked any progress; the Iranian media and conservative political circles were awash with condemnation of Khatami for as much as being present at the same venue as a US president. Today, by contrast, the public are being prepared by Iran's state-controlled media for the prospect of talks with the US. The official Islamic Republic News Agency even proclaims a "new US stance" towards Iran.

A dialogue for change

The western media misread the signals during this crisis. Iran's radical political factions could gather only about 200 Basij protesters outside the British embassy in Tehran (a city of 12 million people); there was no public appetite or political backing for embroiling Iran in an escalating international confrontation. It seems that here too, Ali Larijani was a key player in avoiding this danger.

Ahmadinejad did make the ceremonial phone-call to the Iraqi prime minister, Nouri al-Maliki, on the morning of 29 April announcing Iran's participation in the Sharm al-Sheikh conference. But it is Larijani who visited Iraq to evaluate and set Iran's ground-rules for the summit; his schedule included meetings with al-Maliki himself and Grand Ayatollah Ali al-Sistani.

Iran's efforts towards rapprochement with the US - notably the offer in 2003 to negotiate a "grand bargain" with the Bush administration - have frequently been rebuffed. But the strategic balance has shifted in Iran's favour in ways that make US rejection of this option today more problematic. The combination of the "war on terror", the crisis in Iraq and the war in Lebanon has helped raise Iran's influence in Shi'a-dominated Iraq and across the middle east.

Many of America's European allies, as well as voices in the United States - including the defence secretary Robert M Gates, a member of the Baker-Hamilton commission which advised engagement with Iran - seek a fresh start with Tehran. Sharm al-Sheikh presents America with the choice to begin to unfreeze relations. True, this would entail a major reversal of US foreign policy, but a rational calculation would suggest to the US that its own best interests lie in such a course. The US-based Iran experts Vali Nasr and Ray Takeyh are among those who have consistently argued that the path of dialogue will bring about "a more pluralistic and responsible government in Tehran".

There are glimpses of light. The US Olympic committee - with the full blessing of the state department - has invited Iranian wrestlers to train in the US in preparation for the 2008 Beijing Olympics, "as part of an effort to increase US ties with the Iranian people". Perhaps "wrestling diplomacy" lacks the easy ring of the "ping-pong diplomacy" that opened the door to the historic reconciliation between the US and the People's Republic of China in the early 1970s. But it may be a more fitting analogy for the convoluted contest between Washington and Tehran.