Russia's Syrian bombing gives boost to Iran
While Russian cruise missiles were flying over Iran towards targets in Syria on Wednesday, Iran's Supreme Leader, Ayatollah Ali Khamenei, was delivering a strongly worded speech ruling out the need for further political dialogue with the US.
"Talking to the US will not hold any benefits for us," he told an audience of Revolutionary Guards. "On the contrary, it will be extremely detrimental."
It may not be a complete coincidence that the Ayatollah was addressing members of the Guards, the very same organisation now believed to be playing a key role in planning and supporting Russia's Syrian intervention.
To young Iranians buoyed up by the nuclear deal and already looking forward to the prospect of their country opening up to the West, the Ayatollah's remarks came as a blow.
But in the context of President Putin's latest moves, they seem less surprising.
Russia joining the war in Syria is a major boost to Iran's involvement in Syria.
It also adds weight to Iran's position as a key power in the Middle East.
For much of the past 15 months, there have been repeated sightings of the powerful Revolutionary Guards commander Qasem Soleimani apparently shuttling between Damascus, Baghdad and Tehran.
It is now established that he has been playing a key role in setting up and supporting the Shia militia groups battling so-called Islamic State (IS) fighters in Iraq.
The recapture of the city of Tikrit from IS after a year of occupation marked a successful example of joint military action involving the Iranian Revolutionary Guards, the mainly Shia militias and the Iraqi army.
In Syria too, Iranian support for the army and militia groups, including Tehran's ally Hezbollah, seems to be an open secret.
The Iranian media regularly report funerals of Revolutionary Guards commanders killed in Syria as well as Iraq.
And this summer's flood of refugees and migrants into Europe has included many young Afghan Hazaras, who have described to BBC Persian how they were recruited by Iran into special Shia militia brigades and sent to the front line in Syria.
Their stories back up claims widely reported and pictured on social media this year.
In July, Gen Soleimani apparently resurfaced in Russia where reports - neither confirmed nor denied by Tehran and Moscow - said he was beginning to put in place the plans that led to this week's Russian offensive.
Born: 11 March 1957
Since 1998 he has been commander of the Iranian Revolutionary Guards' elite Quds Force, reporting directly to Iran's Supreme Leader, Ayatollah Ali Khamenei.
Has emerged from a lifetime in the shadows directing covert operations abroad to achieve almost celebrity status in Iran.
Since 2012 he has helped bolster the Syrian government, a key Iranian ally, during the Syrian civil war.
Also assisted in the command of combined Iraqi government and Shia militia forces that advanced against so-called Islamic State.
Visited Moscow in July to discuss possible Russian military intervention in Syria.
There has been no official comment from Tehran so far on the Russian operation.
But the tone of Iranian media reporting about it has been overwhelmingly positive, with much stress on the fact that it is happening as part of a joint coalition against IS, along with Iran, Iraq and Syria.
Russia's intervention means Iran is no longer the only foreign state to have militarily intervened in support of Bashar Assad.
It can now claim to be part of a major new military alliance with a former world superpower as an ally.
From the Iranian perspective, Russian intervention opens up a new possibility to challenge the US-dominated world order - something Iran's hardliners have dreamed of for decades.
But they are not the only ones celebrating Russia's intervention.
According to Ahmad Naqibzadeh, a professor of international relations at Tehran University, it's a development that also suits moderate politicians.
For them, he explains, Russia's decision to back Bashar Assad and attack all the groups opposing him means it's more likely all sides in the Syrian conflict will eventually have to come to the table - without pre-conditions - to find a political solution to the conflict.
"Convincing the West to stop insisting on the removal of Bashar Assad from power would be a victory for Iranian foreign policy and would then facilitate the normalisation of ties between Iran and the West," he told the BBC.
According to Mr Naqibzadeh, key policymakers around Iran's President Rouhani are also hoping the Russian campaign might actually bring the US and Iran closer together.
In a bid to persuade Iran not to throw everything behind Russia, they think the US could adopt a more conciliatory policy, he explains, and this would give Iran the opportunity the moderates are looking for to break out of the current isolation.
Judging by Ayatollah Khamenei's latest remarks, rapprochement with the US is the last thing on his mind.
An Iranian academic close to President Rouhani, and speaking to the BBC on condition of anonymity, says the idea of normalising ties between Iran and the US is something that deeply worries the Ayatollah.
"He believes the Americans are waiting for an 'Iran without Khamenei' in order to take Iran completely into their camp," the academic said.
The Ayatollah is the ultimate decision-maker in Iran's foreign policy, and he has made clear that he sees the US as an eternal enemy.
But the irony is not lost on many observers both inside and outside the country, that in order to combat one old enemy, the US, and to rescue his Syrian ally, Mr Khamenei is now turning to Russia, a country with which Iran shares a much longer history of adversity.
In the coming months, Iranians will be watching to see if the Ayatollah's gamble pays off, or whether Mr Putin's entry into the fray will draw Iran and its allies even deeper into the Syrian quagmire.