Iran's fraught nuclear negotiations with six world powers enter a critical phase in Moscow today, with the gap too wide to expect a significant breakthrough but the stakes too high to allow a breakdown.
Heading Iran's delegation is Saaed Jalili, a soft-spoken hardliner whose political star is rapidly rising. Admirers are urging him to run for president next year. Their calls are being made on new blogs and websites, including one linked to an influential hardline ayatollah.
But Mr Jalili is brushing aside the flattery as he concentrates on the two-day meeting in Moscow.
His immediate goal is to ease European Union and US sanctions targeting the jugular of Iran's economy: its oil and banking sectors. These come fully into effect in just two weeks, but have already inflicted considerable pain.
The West's immediate aim is to persuade Iran to suspend its enrichment of uranium to 20 per cent, which is in striking distance of producing bomb-grade fissile material. Iran insists its nuclear programme is solely peaceful, to generate electricity and produce medical isotopes.
Failure in Moscow would raise the threat of Israeli military action against Iran's nuclear facilities. That could ignite a new war in the Middle East that would send oil prices soaring, crippling a global economic recovery and imperilling US president Barack Obama's re-election bid.
So Mr Jalili, Iran's chief nuclear negotiator, carries a weight of responsibility on his 47-year-old shoulders.
He is like few other diplomats, let alone any head of state. He insists on lugging his own suitcases on trips abroad, leads a devout and ascetic life, and is said to have memorised the Quran.
His world view - and enduring suspicion of the West - was forged during Iran's eight-year war against Iraq.
Like Mahmoud Ahmadinejad, Mr Jalili served in the Revolutionary Guards but, unlike the Iranian president, he spent most of his time on the front line. Mr Jalili lost his lower right leg in the 1980-88 war and is said to have survived two Iraqi chemical gas attacks.
"Remember that, from Tehran's point of view, Iraq was acting as a proxy for the United States," said a European official close to the nuclear negotiations.
Like most Iranian envoys, Mr Jalili lectures western officials on Iran's long list of historical grievances whenever he gets the opportunity. His complaints about western perfidy are delivered through interpreters: he speaks virtually no English.
Although he is a hardline ideologue, the West views him as a reliable interlocutor because he has the approval of Iran's equally hardline supreme leader, Ayatollah Ali Khamenei, who regards Mr Jalili as an obedient and loyal devotee.
The ayatollah has always controlled Iran's nuclear file behind the scenes but recently gave Mr Jalili a new title, describing him as his "personal representative".
That public endorsement was the first time Mr Khamenei has directly invested his legitimacy in talks with Iran's western adversaries. His involvement means any deal struck with the six powers - the US Britain, France, Russia, China and Germany - is unlikely to meet any resistance at home.
Equally, should the ayatollah pull the plug on the nuclear negotiations if he deems the so-called P5+1 is not offering enough, he can rely on Mr Jalili not to contest his decision.
Mr Jalili became the director general of Mr Khamenei's office in 2001, but remained a relatively obscure figure until 2005 when Mr Ahmadinejad, an old friend, came to power and appointed him deputy foreign minister for European and US affairs.
Critics complained he had little diplomatic experience and said he got the job because of his hardline politics and loyalty to the president.
Mr Jalili is said to have helped Mr Ahmadinejad with a remarkable 18-page letter to George W Bush in 2006. The US former president was informed that western-style democracy and liberalism had failed and it was time for him to return to religion. Mr Bush never replied.
A year later, Mr Ahmadinejad appointed Mr Jalili secretary of Iran's Supreme National Security Council, automatically making him chief nuclear negotiator.
He was a controversial and surprise choice. The West feared it signalled Tehran would take a harder line in the nuclear standoff while prominent Iranian conservatives complained that Mr Jalili, then just 42, lacked the negotiating experience to secure Iran's nuclear rights.
Muhammad Sahimi, an Iran expert at the University of Southern California, said that even in Iran, Mr Jalili is "not considered a very smart man."
Mr Jalili studied at Imam Sadeq University, a conservative institution where many Revolutionary Guards and members of the Basij paramilitary are educated. He wrote a book, The Foreign Policy of the Prophet, a development of his doctorate thesis, Paradigm of Political Thought of Islam in the Holy Quran.
Mr Jalili is said to have spoken at length about his thesis during a meeting on Iran's nuclear programme with international envoys in July 2008, forcing some to stifle yawns
Nader Entessar, an Iran specialist at the University of Southern Alabama, said Mr Jalili's views have been tempered in recent years by his exposure to western envoys. "He's also very low-key and even-tempered, which could be useful in contentious negotiations," Mr Entessar said.
Unlike Mr Ahmadinejad, Mr Jalili does not revel in the limelight, nor does he share the president's love of bombast and bluster.
When Iran's supreme leader and president fell out publicly last year, Mr Jalili swiftly made clear his allegiance was to Mr Khamenei, who has sidelined Mr Ahmadinejad in the nuclear negotiations.
The president's supporters have hit back by sniping at Mr Jalili's handling of the talks.
"Jalili will always serve whoever has the upper hand," Mr Sahimi said. "Ahmadinejad tried to remove him from the nuclear negotiations, but Khamenei blocked it."