In a desperate scramble to confront a looming onslaught on Baghdad by the jihadi group Islamist State in Iraq and the Levant (Isis), senior officials in Britain, the US and Iran indicated this week that the three countries will co-operate diplomatically - but not militarily - in tandem with the Iraqi government.
The news raised alarm bells among supporters of Israel and Saudi Arabia, the West's two key allies in the Middle East. Both countries have strong reasons for pressing for Iran's continued containment.
Israel resents any rapprochement with a potentially nuclear-armed Iran committed, at least rhetorically, to the Jewish state's destruction, and to supporting Hizbollah.
Sunni-dominated Saudi Arabia, meanwhile, historically views Shia-led Iran as its main rival as the regional superpower, and a pernicious cause of instability in its own Shia-majority, oil-rich Eastern Province.
US Senator John McCain, long a vocal supporter of the Islamist-led insurgency in Syria, was predictably most bellicose in his outrage, calling the Iran move "absolute folly", while British newspapers waxed lyrical on the supposed sudden transformation of Iran from international pariah to the West's new best friend.
It is folly to think that a dramatic geopolitical realignment is on the cards
What is most extraordinary, however, is the failure of politicians and pundits alike to ponder a more obvious, if less sensational, reality.
For more than a decade, when geopolitical pragmatism dictated - as it clearly does again today - Iran has offered to work closely with the West. After the September 11 attacks, for instance, Iran - which has no sympathy for al-Qaeda - rounded up hundreds of Arab terrorists, and provided intelligence to Washington to aid the war on terror.
As recently as 2009, Tehran was publicly offering to help Washington rebuild and stabilise Afghanistan, while, in 2007, the two countries held (ultimately unproductive) talks on Iraq - again following offers by Iran to work with the US to establish some kind of normalcy in Baghdad.
None of this is to suggest that there are not myriad criticisms to direct at the Iranian regime, that fears of a nuclear-armed Tehran are unfounded, or that its leaders are not deft at engaging in diplomatic shenanigans.
Surely neither Washington nor London need reminding of any of that.
Indeed, for that very reason what is "folly" is to envisage that, as a result of another temporary diplomatic engagement between Washington and Tehran, a dramatic geopolitical alignment in the region on the part of Washington - and at the expense of ties with Israel and Saudi Arabia - will suddenly be on the cards.
As Isis closes in on Baghdad, one can but hope the pragmatists in both Washington and Tehran win the day.
The massacres of Shia in Baghdad and the destruction of their shrines will only further embolden jihadi groups and set the entire Middle East ablaze in an orgy of unprecedented sectarian violence - an outcome that will serve no country's interest.