The truce led by Russia and Turkey is holding – but the different players in the peace process still have conflicting objectives

A tentative ceasefire is holding in most parts of Syria as the truce’s main backer, Russia, pushes for a United Nations resolution, which it says would start a political process that could quickly take the steam out of six years of war.

As the most destructive year of the conflict drew to a close, Moscow and Ankara were moving frantically to secure the deal, which each side claimed offers the best hope yet of an end to a war that has had few boundaries and no apparent endpoint.

The UN security council welcomed the deal and plans for fresh peace talks but the resolution comes against a backdrop of deadlock among members supporting different approaches.

Even as the bilateral push intensified, opposition groups warned that texts of agreements to be put to the UN this weekend failed to enshrine a key element of their cause – a political transition away from Syrian leader Bashar al-Assad towards a new governing body that would rebuild the country and reshape its body politic.

The demand was central to previous US and UN-led initiatives and senior opposition leaders said they would consider the ceasefire deal null and void unless it was honoured. The standoff marks a moment of reckoning for Russia and Turkey which, after earlier pursuing competing visions for postwar Syria, have in the past six months found much common ground and, along with Iran, are rapidly carving out spheres of influence across the once sovereign state.

Turkey, a backer of mainstream and Islamist groups, has moved away from its earlier insistence that Assad be defeated militarily, but remains adamant that he be removed in a political process. Russia, meanwhile, has hedged, insisting repeatedly to opposition negotiators that it is not wedded to the embattled president, but refusing to commit to a transition.

The bilateral push has come when the anti-Assad opposition is at its weakest point in the war. Having been bombed out of Aleppo and steadily abandoned by its regional backers, six of the seven main armed groups have signed on to the peace initiative, after receiving assurances that aid will start to flow to besieged areas if it continues to hold.

“What could we do?” asked a senior member of Jaysh al-Islam, one of the signatories to the truce. “Our backers [Saudi Arabia] have been nowhere to be seen all year. There’s no one from the Gulf here at all.” Qatar, a prominent backer of the opposition and ally of Turkey, has sharply scaled back its support in the past six months. Diplomatic sources confirmed to the Observer that the reduced backing is partly due to a threat from senior Russian officials. “That happened in around August,” said one senior regional official. “But the other reason they withdrew was they did not want to be associated with a losing cause.”

While things have fallen into line for Russia and Turkey, not all stakeholders in the crisis are satisfied. Iran, which is not a driver of the ceasefire plan, but is a pivotal player in Syria’s short-term future, remains implacably opposed to Assad’s exit. Along with Russia, it has invested blood and treasure in stabilising him and safeguarding the remaining pillars of regime influence. However, now that battlefield wins have effectively ensured Assad cannot lose, very divergent views are emerging about what comes next.

“The Russian and Iranian views on Syria are diametrically opposed, but the west is not capitalising on that,” said one senior opposition member. “The Iranian model is weak government, geographical areas of complete control by pro-Iranian forces that would guarantee a territorial passage from Iraq to Lebanon. There will be forced migration and cleansing.

“The Russians on the other hand want a unified Syria, a strong centralised government and their own interests, specifically their military bases and contracts, being secured. The regime is now divided into pro-Russia and pro-Iran elements, with Assad being closer to Iran.”

Though Assad casts himself as a battle-hardened leader who has prevailed over his foes, officials in Iran, Russia and Turkey are privately scathing about him, his military and the country’s political leadership. Far from presiding over a secure, sovereign state, the Syrian leader has little leverage over what happens next.

Turkey, which had pushed for a no-fly zone near its border for much of the war, has spent the past five months building a zone of influence inside Syria, within a 60-mile gap between the towns of Irfin and Jarabulus.

Ankara has used Syrian rebels as shock troops in a push against the Islamic State terror group which retains a presence in the area, and has backed them extensively with its own tanks and elite forces. However, even more pressing for the Turkish leadership than Isis is the presence of Kurdish groups that have used the chaos of war to move into the area and, in doing so, threatened to create a Kurdish presence along Turkey’s entire perimeter with Syria.

The Turkish incursion was made with Russian political cover and has served the dual purpose of thwarting Kurdish ambitions and curbing Isis. It has carved out a zone of influence which, in Turkish officials’ minds, limits the ability of Syria’s restive Kurds to link up with the outlawed Kurdish organisation PKK in southeastern Turkey, which Ankara continues to fight.

Iran too has a significant stake. Having led the ground fight for Aleppo, it aims to secure a foothold in eastern Syria, which it will reinforce with demographic shifts of Shias for Sunnis, and build through a corridor under its control, from Tehran to the Mediterranean.

Iran has long viewed Damascus as an essential pillar of its regional ambitions, vis-a-vis Hezbollah, whose presence in southern Lebanon menaces Israel and whose role in Syria helped lead Iran and Assad to the point of victory. However, establishing strategic depth, stretching through Iraq, where Iran also has a whip hand, consolidates a regional influence nearly 38 years in the making.

Amid the heft of historical ambitions being realised, and the first tangible diplomatic momentum of the war, there is now a sense that things are shifting in Syria. An all but vanquished opposition said it would again pick up arms if its demands were not met at the United Nations security council and if regime helicopters and Hezbollah did not honour the ceasefire. However, the groups have less leverage than when their backing remained robust, and before Russia’s 15-month military blitz.

“There has been huge pressure to sign [the ceasefire deal],” said a senior member of Ahrar al-Sham. “They gave us 48 hours. There are two documents, one signed by the armed groups and the other by Turkey and Russia as a guarantor. They gave the regime the same set of documents and they returned them with 12 changes, two of them striking, the most important of which was not to include Geneva 1 as a framework for a solution.

“Geneva 1 dictates that there should be a governing body with full authority of the president, according to the Syrian constitution. It makes the future of the president very clear. By ignoring that you are ignoring the fact that there is a need for a real political transition.”

Russia in particular has been determined to cast itself as a peacemaker in Syria, after a protracted role as a bludgeoning power. Its diplomatic push has sidelined UN-led negotiations, and the US.

Three weeks before the inauguration of Donald Trump, Vladimir Putin is close to realising a goal of bringing relative stability to one of the most intractable conflicts of modern times, after helping ensure all other attempts failed. If it works, it will be largely on his terms, giving Russia a stake in the rest of the Middle East for the first time since the end of the Soviet Union.