Iran and Russia may find a way to push past their strategic differences and make the ceasefire work, but it will be much more difficult to forge agreements on Syria's other intractable issues at the upcoming peace conference.
In mid-December, after a final military assault on Aleppo alongside Syrian regime forces, Russia announced that the city was free of rebels. A week later, Moscow and Turkey signed a ceasefire agreement. The Kremlin seems eager to ring in Donald Trump's presidency with a renewed effort to find a political solution and end the war, beginning with peace talks scheduled to be held in Astana, Kazakhstan, at the end of January.
Yet the ceasefire is under threat only days after it began, with Hezbollah and Assad regime forces fighting rebels in the Damascus suburbs of Wadi Barada and East Ghouta. Ten rebel factions have already threatened to boycott the Astana talks unless the ceasefire is fully implemented.
Wadi Barada has been under siege since July, when Syrian and Hezbollah troops cut access routes to a spring that provides much of the capital's water. Under the direction of its Iranian patron, Hezbollah has been working diligently to strengthen its control over the suburbs, in line with a wider plan to establish a Sunni-free corridor linking Iran to Lebanon via Iraq and Syria. This entails securing Damascus as the Alawite capital, with Bashar al-Assad staying on as president. The group aims to finalize this corridor before negotiating any division of power in Syria, so it is sidestepping the ceasefire as much as possible.