In a changed world, Syrian rebels’ assault brings foreboding

At the time, it looked as though Damascus could be overrun by Islamic State (IS) militants, as they captured large swathes of territory in eastern Syria, with Assad's soldiers struggling to defend key locations. So, in the autumn of 2015, Putin gave the green light, authorising Russia's military intervention, which turned the tide in Assad's favour.

Advanced Russian warplanes attacked rebel strongholds from the air while working with Iranian-led forces on the ground, including Hezbollah fighters from Lebanon. Together, they let Assad reclaim control of all Syria's major cities, including the northern city of Aleppo—a rebel resistance hub from 2011.

Still not in full control

Pivotal though Russian and Iranian efforts were, they did not achieve total victory. When major hostilities finally ended in 2020, Assad still only controlled around two thirds of Syria. Large areas in the north remained in the hands of opposition groups, including the US-backed Kurds and several Islamist and jihadist militias in Idlib.

Assad's inability to re-establish control over these vital areas led to the rebel groups launching their surprise assault on Aleppo in the past few days. Local security forces report that the rebels fighting in Aleppo, Idlib and Hama provinces in north-west Syria include some units backed by Turkey, as well as the Islamist Hayat Tahrir al-Sham (HTS)—the former al-Qaeda affiliate in Syria. For its part, Turkey has denied urging the rebels to attack Aleppo.

This time, it is not 2015, and there are serious concerns about whether the regime will survive the onslaught. Nearly a decade after the Russians and Iranians saved Assad's skin, the global geopolitical landscape has changed dramatically. It is by no means certain that his allies will repeat the feat today.

Dogs in other races

Whether Russia and Iran could (or would want to) help Assad is questionable given their current involvement in other conflicts. Russia may be making ground in Ukraine but its military has suffered huge losses there since the invasion in February 2022, so much so that Moscow has had to redeploy some of its forces in Syria.

Iran also finds itself on the defensive, given Israel's direct attacks and its near-obliteration of Iran's proxies in Gaza (Hamas) and southern Lebanon (Hezbollah). Back in 2015, Tehran could rely on a strong Hezbollah and other Iran-backed militias in countries like Iraq to help Assad. Today, it is struggling to find the personnel.

Iran has already sent at least 300 fighters into Syria from Iraq in recent days, but Tehran's ability to send more reinforcements is limited given the heavy losses that Hezbollah has suffered in Lebanon at the hands of Israel's military and intelligence services.

Building a head of steam

The rebels' success in seizing control of Aleppo certainly represents the anti-Assad forces' biggest victory in years. The regime had held Aleppo since capturing what was then Syria's largest city after a siege in 2016 in one of the major turning points of a war that killed hundreds of thousands of Syrians.

Moscow's concern about the potential loss of a key Middle East ally has led Putin to sack a senior Russian officer commanding forces in Syria. But while Russian and Syrian warplanes are currently bombing rebel positions in Idlib, they are clearly struggling to contain the rebels' advance towards the strategically important city of Hama.

For his part, Assad has vowed to crush the rebel uprising in a counter-offensive, calling them "terrorists" who "understand only the language of force".

But for his neighbours, an escalation in the Syrian conflict risks further destabilisation in a region already suffering from war in Gaza and Lebanon. They will all be hoping for a swift resolution one way or another.