BEIRUT -- The international community is mounting its most serious effort yet to end the nearly 5-year-old Syrian war, rallying around a second round of talks in Vienna this weekend amid the emergence of a Russian proposal that calls for early elections.
But the global push for peace so far excludes any of the Syrian players, and experts say any hasty decisions risk leading to even greater bloodshed.
While world leaders seem to be in agreement that the time has come to put an end to the carnage in Syria that has killed more than 250,000 people, there is still no clear roadmap on how to get there.
Still, the stepped up diplomatic activity, coupled with the U.S. decision to send special operation troops into northern Syria -- something the Obama administration had long sought to avoid -- reflects a new urgency and a shift in dealing with the world's most intransigent conflict.
The Russian proposal calls for drafting a new constitution within 18 months that would be put to a popular referendum and be followed by an early presidential election. But it makes no mention of Syrian President Bashar Assad stepping down during the transition -- a key opposition demand and a sticking point in all previous negotiations to end the civil war.
Russia's military intervention in Syria has raised Moscow's profile when it comes to Syria and given Russian President Vladimir Putin a stronger say in how to end the conflict.
"This is really the first serious effort on the part of the United States and Russia to bridge the divide, to come up with some concrete ideas about the broad contours of a diplomatic settlement," said Fawaz Gerges, a Middle East expert at the London School of Economics.
The divides have narrowed considerably, he said, adding that the Americans and the Russians now seem to see eye-to-eye on restructuring the political system by drafting a new constitution and holding early elections.
The involvement of Russia and Iran, two key allies of Assad, is essential in any talks on Syria. Iran had been excluded from last year's talks in Switzerland, but attended the talks two weeks ago in Vienna along with its arch regional rival, Saudi Arabia, a key backer of the rebels fighting to topple Assad.
The Syria conflict has turned into a proxy war between regional and international foes, and observers have long said that any attempt to end the fighting will have to come from an agreement between the warring parties' regional backers, who can then strong-arm the groups they support into making the necessary concessions.
At the initial talks in Vienna on Oct. 30, the U.S., Russia, Iran and more than a dozen other nations agreed to launch a new peace effort involving Syria's government and opposition groups.
The second round on Saturday again excludes the Syrians, and it is not clear yet if the Russian proposal has been coordinated with the Syrian government. The proposal also does not address a mechanism for bringing about a cease-fire ahead of talks.
"The political future of Dr. Bashar Assad should only be decided by the Syrian people in democratic elections," said Iran's deputy foreign minister for Arab and African affairs, Hossein Amir-Abdollahian, speaking in Beirut on Wednesday following a visit to Moscow.
But that is easier said than done.
Syrian legislator Sharif Shehadeh, a member of the ruling Baath party, told The Associated Press there will be no presidential vote before Assad's latest term ends in 2021. He added that parliamentary elections are an internal Syrian affair and that it was still too early to hold them.
Assad was elected for a third seven-year term last year in an election boycotted by the opposition and dismissed as a sham by its Western supporters. The vote was held only in government-controlled areas of Syria, which have since shrunk further, with Islamic extremists seizing more areas of the country.
Allies of the Syrian government recognized the legitimacy of the election, and the fighting worsened.
Russia began launching airstrikes in support of Assad's troops on Sept. 30. The stated aim was hitting at Islamic State extremists, but the airstrikes have improved the position of Assad's forces, who have gone on the offensive in some areas. On Tuesday, government troops broke a siege imposed by the Islamic State group on a northern military air base since 2013, marking the first major achievement by Assad's forces since Russia began its airstrikes.
Hezbollah leader Sheikh Hassan Nasrallah, whose fighters have played a key role in backing Assad, said the latest battlefield gains by government forces show that their rivals "should move toward a political solution without preconditions that are impossible to achieve."
Prominent Syrian opposition figure Haitham al-Maleh said the very fact that Russia is carrying out airstrikes in support of Assad's troops shows Moscow wants the "current regime to stay," adding that the opposition will not accept any role for Assad during the transition. His words reflect the deep mistrust among Syria's myriad opposition and rebel factions of any proposal emerging from the Russians.
Iran, too, remains a wild card. It is unclear how far Tehran, which has pumped billions of dollars into supporting Assad, would compromise following its nuclear deal with the West.
Robert Ford, a senior fellow at the Middle East Institute and a former U.S. ambassador to Syria, warned that a new constitution and new elections can only be held after serious governance changes are made.
"Unlike diplomats meeting in Vienna and Geneva, Syrians have seen firsthand how the Syrian government operates and how it manages elections," Ford wrote in an article published by the think tank this week. "As hard as those negotiations surely will be, rushing to elections without serious, perceptible progress on the rule of law first is a sure-fire scenario to make the Syrian civil war even nastier."
Even though the latest talks represent the most serious opportunity yet, their success is a long shot, Gerges said.
"Not only because the devil is in the details, but because we are talking about regional powers that don't see eye-to-eye and you are talking about multiple factions that are going to fight until the end," he said.