Iran's supreme leader, Ayatollah Ali Khamenei, has weathered some critical moments over the last quarter of a century- the US-led invasion of Iraq in 2003 when Tehran feared it would be the next target, the disputed re-election of Mahmoud Ahmadinejad, which shook the legitimacy of his rule and the acrimonious years that followed as sanctions hit the country's economy.
Perhaps the biggest decision of his career, however, was the one he had to make this week.
The historic deal struck in Vienna could not have happened without Khameni's blessing.
He has the final say in all state matters in Iran and his decision may define his leadership.
On one side of the negotiating table of the 22-month talks sat seven parties struggling to secure a formula that would allow a comprehensive nuclear agreement with Tehran, which will have profound implications for the Middle East. On the other side, there was one man not actually present but whose view was decisive. No one doubted who that person was.
Khamenei knows only too well the weight his verdict carries.
He wants to go down in history as the man who persuaded the west and the US in particular to “recognise the Islamic republic’s right to a peaceful nuclear programme” against all odds, and despite numerous UN security council resolutions demanding a complete halt to its nuclear activities.
He is determined not to be cast as the leader who yielded to sanctions and
drank from the “poisoned chalice”, a term Khamenei’s predecessor Ayatollah Rouhollah Khomeini used when he agreed to sign a UN-brokered truce to end the country’s eight-year war with Iraq in 1988.
That conflict was the longest conventional war of the last century and cost 500,000 Iranian.
Many in Khomeini’s inner circle opposed making peace, arguing that the “sacred defence” had to continue until Saddam’s rule collapsed.
In the end, however, pragmatism prevailed and Khomeini heeded the moderate forces.
Khomeini died shortly after accepting the truce, and a year later Khamenei, then the country’s president, was elevated to the life-time position of supreme leader. He was left with the daunting task of steering Iran through the difficult post-war era.
This week, Khamenei found himself in a similar position to his predecessor. Just as during the war with Iraq, two major forces are at play within Iran.
One opposed compromise with “the enemy” and sees the deal as a humiliation for Tehran, while the other, made up of reformists and moderates, wanted an end to the nuclear saga.
Once again, Iran’s leader found himself caught between the two forces.
In the months before the agreement, many hardliners warned that moderates were forcing Khamenei to drink from the “poisoned chalice”.
"Whether we like Khamenei or not, whether we consider him as a dictator or a dear leader, he has quite successfully managed to keep Iran stable in a volatile region struck by war and instability," Ali Alizadeh, an Iranian analyst based in London, said.
“The talk of drinking from a poisoned chalice is something that is uttered from both internal and external hardliners who want to portray this deal as a defeat for Khamenei, which I think is a mistake.”
Alizadeh described Khamenei as a classic conservative in the same mould as Henry Kissinger, "whose main concern in the past 14 years since the beginning of 2000s has been to secure the stability of the Islamic republic".
"He may well have just achieved that, and this agreement will change the paradigm from Washington to Riyadh, heralding a new era in the Middle East and international relations," he said.
The Guardian