January 6, 2017 | Fritz Lodge – THE CIPHER BRIEF – USA – The December 30 ceasefire in Syria, brokered by Russia and Turkey, has for the most held throughout the country, despite violence undermining the pact.  This ceasefire is the third of its kind attempted within the space of a year. But with backing from Russia and Turkey, as well as seals of approval from both the High Negotiations Committee of the Syrian opposition and the government of Syria, this agreement may have what it takes to survive the intermittent violations that brought down its predecessors.

Nevertheless, this new collaboration between Moscow and Ankara on Syria policy has a long way to go before planned peace negotiations take place in Astana, Kazakhstan later this month. Fighting in the Wadi Barada valley near Damascus continues to delegitimize the existing ceasefire and has already led some groups to freeze participation in the Astana talks. At the same time, the absence of major groups, like the Islamist Jabhat Fatah al Sham (formerly Al Nusra Front) and the Kurdish PYD (Democratic Union Party), from inclusion in the ceasefire obscures the role that they will play in any future negotiations.

However, with the Obama administration on its way out and President-elect Donald Trump’s intentions largely unclear, the most important hurdle to Syrian peace now lies in the fragile detente between the war’s three most important foreign backers: Turkey, Russia, and Iran.

For the moment, this tripartite relationship sits in a delicate balance. Russia, which is Syrian President Bashar al-Assad’s primary backer, and Turkey, the most powerful supporter of the anti-Assad opposition, both appear committed to the pursuit of high-level peace negotiations and possible collaboration on combatting “terrorist” groups. Meanwhile, says Visiting Fellow at the Washington Institute Fabrice Balanche, “the Iranians are discreet, preferring to leave the spotlight on (Russian President) Vladimir Putin.”

Yet, at the end of the day it is Iran, not Russia, that wields the most influence over the Assad regime. Moscow may have tipped the battlefield towards the Syrian government by providing weaponry and aerial bombardment, but it is the Islamic Republic that provides Assad with his scarcest resource, manpower. Without the assistance of tens of thousands of fighters from Hezbollah – and Iran-backed militias from Iraq, Afghanistan, and Pakistan – Syrian forces would never have been able to assault and reoccupy Aleppo. Similarly, writes Balanche, “the Islamic Republic has been the main economic supporter of the Assad government since the beginning of the conflict in 2011.”

Russia does appear to have taken over Iran’s role as the primary power broker in Syria, primarily because, as Barak Barfi, Research Fellow at New America, writes, “the rebels never trusted the Iranians… [and] have more faith in Moscow to keep [Iranian] militias in check.” However, this does not mean that Iranian interests now align with Russia. For Moscow, the war in Syria is an opportunity to enhance Russian prestige on the world stage, reinstate the Kremlin as a major player in Middle Eastern affairs, and acquire leverage for future negotiations with western powers. Tehran, on the other hand, views Syria as a vital link in the chain that connects Iranian proxies from Lebanon to Iraq. Thus, where Russia might be happy to make key compromises in order to negotiate a successful peace agreement and walk away victorious, Iran’s goals in the Syrian civil war are far more maximalist. Tehran envisions victory for Assad, as well as the decisive defeat of all armed Sunni groups in Syria from ISIS to Turkish-backed rebel groups, and it is happy to undermine ceasefires or talks if it feels that vision is under threat. For instance, Iranian militias were reportedly responsible for initially blocking the negotiated evacuation of rebel fighters and trapped civilians from Aleppo in December.

On the other side of the negotiating table, Turkey is in a strong position to influence rebel actors. According to Barfi, “Most of the rebel groups that agreed to the ceasefire are based in the northern provinces of Aleppo and Idlib, and depend on Turkish largesse for their continued prosperity.” This is especially true for Syrian rebels who operate under the Turkish-backed “Euphrates Shield” coalition, which occupies a large swath of territory north of Aleppo. However, as Barfi points out, even groups that received funding and supplies from the U.S. or other regional actors “are ultimately beholden to Turkey for passage through its borders.”

After the shooting at Reina nightclub in Istanbul, which was claimed by ISIS and left 39 people dead, Ankara is both well positioned and newly motivated to cut a deal with Assad and Putin in order to focus on ISIS and other “terrorists” in Syria. However, for Turkey, this includes the Kurdish PYD –  Syrian sister organization to Turkey’s PKK. Unfortunately, PYD fighters also form the backbone of the U.S.-backed Syrian Democratic Forces (SDF). This presents a difficult problem for the primary American objective in Syria, which is to capture the ISIS capital of Raqqa.

Finally, a major sticking point for both the current ceasefire and any future peace negotiation will be the status of Jabhat Fatah al Sham (FTS). The Jihadist, al Qaeda-aligned group has been excluded from the current ceasefire, but FTS is one of the most powerful militias in Syria, and its forces are mixed in with other groups across the country. This becomes a problem when, during the current violence in the Wadi Barada valley for instance, government forces claim that their attacks don’t violate the ceasefire because they are targeting FTS but other groups get caught up in the fighting. Finding a way to deal with FTS will be vital to the success of this or any future ceasefire.

However, the fate of Syria must ultimately lie with Assad. Russian and Iranian interventions have breathed new life into his regime, but even with this aid, Assad cannot kill all of his enemies. For stability and peace, he will need to make difficult compromises, whether he is willing to do so remains to be seen.

Fritz Lodge is an international producer at The Cipher Brief. Follow him on Twitter @FritzLodge.