Geneva, Switzerland - Negotiations aimed at finding a political solution to the war in Syria are set to begin at the United Nations headquarters in Geneva on Thursday as a nationwide ceasefire steadily falls apart and UN officials soften their expectations on achieving any major breakthroughs.

The intra-Syrian talks - which will bring together representatives of the Syrian government and the opposition, along with their respective international backers - will resume after UN envoy Staffan de Mistura broke them off nine months ago as several rounds of meetings ultimately led to an escalation of violence across the country.

The talks are part of the latest initiative to bring an end to a destructive six-year war that has killed nearly half a million people, injured more than a million, and displaced over 12 million - half of the country's prewar population. They come on the heels of multilateral meetings in the Kazakh capital of Astana aimed at consolidating a shaky nationwide truce and paving the way towards political negotiations.

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But the ceasefire has steadily fallen apart and an all-out fighting has returned to key areas across the country, as tensions between the truce's guarantors - Russia, Turkey and Iran - steadily rise.

[Armed groups] participating in Geneva are afraid that any political concession they may make would leave them vulnerable to political attack and one-upmanship by their more hardline allies. Noah Bonsey, International Crisis Group

Over the weekend, de Mistura evaded questions from reporters as to why he has shied away from using the phrase "political transition" - a term the opposition equates with the removal of President Bashar al-Assad - to describe the goal of the talks.

De Mistura instead said he remained focused on UN Security Council Resolution 2254, a document that mentions the word transition several times but uses vague language too broadly focus on three key issues: governance, a new constitution and new elections.

"I think what we're seeing isn't the UN formally abandoning transition, which would require some drastic action at the Security Council," said Aron Lund, a fellow at The Century Foundation.

"But, we are seeing the UN and several of the nations involved in Syria starting to de-emphasise and circumvent the regime change content of those early resolutions by shifting the debate to topics that are not directly connected to Assad staying or going," Lund told Al Jazeera.

During past rounds of negotiations, the Syrian government has categorically refused to discuss Assad's fate - a sticking point for the opposition - but as the balance of power continues to shift further into the government's hands, the scope and shape of a feasible political solution in Syria may be changing, too.

Russia, whose military intervention in Syria was key in turning the tide of war in Assad's favour, has pushed to restart negotiations since helping to facilitate the government takeover of rebel-held east Aleppo late last year, dealing the opposition its biggest defeat of the conflict.

Moscow's diplomatic lead over Syria, assisted by a growing rapprochement with Ankara and uncertainty surrounding the presidential transition in the US, resulted in the multilateral talks in Kazakhstan in January to consolidate a fragile ceasefire established by Russia and Turkey in December.

The Astana meetings brought representatives from Russia, Turkey and Iran - another chief Assad ally - together with delegates from the Syrian government and officials from armed opposition groups.

And while the first meeting in the Kazakh capital nominally succeeded in creating a "trilateral mechanism" through which Russia, Turkey and Iran would allegedly monitor and enforce the ceasefire, talks faltered in the second round as violence steadily returned to areas across the country.

Renewed fighting in rebel-held Eastern Ghouta and a concerted government push into the neighbouring besieged area of al-Qaboun threaten to tank talks before they even begin.

Under siege since April 2013, the enclave of Eastern Ghouta, in the countryside north of Damascus, could prove to be a sticking point in the talks. An uptick in violence in the area could push Ghouta's controlling rebel faction - Jaish al-Islam - to drop out of the peace talks.

The southern, largely rebel-held province of Deraa, has also seen heavy fighting in recent weeks, pitting a broad collection of armed groups against government troops and allied militias as the latter attempt to push towards a key border crossing with Jordan. If successful, it would effectively split the southern rebel-held strip in two.

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Jordan's participation in the second round of Astana talks hints to the fact that Amman, like Ankara, could also be shifting its agenda away from all-out regime change in Syria.

While infighting among rebel groups is not new in Syria, divisions in Syria's north and strategic changes by chief opposition backers have rendered armed opposition weaker than ever.

"What remains of the negotiation-friendly opposition is seeing its resource base frittered away on sideshow projects by foreign backers like Turkey and Jordan, while the indigenous centre of the anti-Assad rebellion is being cannibalised from within by [Islamists]," said Lund.

Armed groups, particularly in Syria's north, have split in recent months as the international community puts increasing pressure on rebel groups to distance themselves from hardline Salafist groups linked to Jabhat Fateh al-Sham, a group formerly known as al-Nusra Front that changed its named after officially breaking ties with al-Qaeda.

Reuters news agency revealed this week that CIA funding for Western-backed rebels fighting under the banner of the Free Syrian Army (FSA) in Syria's northwest has been frozen since last month's division. And while rebels said they believed the freeze - which includes salaries, training, ammunition, and in some cases anti-tank missiles - was temporary, it is evidence of declining rebel fortunes.

Further detracting from the opposition's bargaining power at the negotiating table is the absence of the dominant Syrian Kurdish faction known as the Democratic Unity Party (PYD), whose armed wing has been a key regional ground ally of the US-led coalition's fight against the Islamic State of Iraq and the Levant (ISIL, or ISIS).

The PYD has repeatedly been barred from the political process because of Turkish objections over the group's links to the Kurdistan Workers Party (PKK) in southeast Turkey, which Ankara has deems a "terrorist" group. Analysts say that Turkey's leverage has forced the UN to choose whether it wants an opposition delegation without Kurds or a delegation without Sunni rebels.

With no actual ceasefire to speak of, and with rebel positions weaker and more divided than ever, the armed opposition is in no shape to consider serious political concessions for fear of losing further relevance and influence on the ground, analysts say.

"I think expectations all around are pretty low," Noah Bonsey, a senior analyst with the International Crisis Group focused on Syria.

"[Armed groups] participating in Geneva are afraid that any political concession they may make would leave them vulnerable to political attack and one-upmanship by their more hardline allies. So … it makes what would already be a very difficult environment for discussions in Geneva all the more tough," said Bonsey.

"None of these previous rounds [of negotiations] have really led to substantive conversations … and even what little was accomplished in the first round of Astana Talks has begun to break down."

Before this week's talks in Geneva, members of the opposition have repeatedly called on the government to build on the failing ceasefire with trust-building measures, including the release of detainees, the end to government sieges and the facilitation of humanitarian aid.

Instead, fighting has expanded. Assad and his allies have continued to make progress on the ground, making it difficult to see how a further weakened opposition could force the government to compromise when it has few negotiating chips available.

"Looking at Syria right now, the opposition really doesn't have an attractive future ahead of it. There's no political horizon on offer except, possibly, an Assadist restoration," said Lund.

"We're now seeing the UN take that ambiguity in one particular direction, reflecting Assad's growing advantage on the ground," said Lund, referring to the steady gains on the ground made by the government and its allies since Russia's 2015 military intervention.

An "Assadist restoration" would entail, among other things, an absorption of opposition elements into the central state led by Assad and an incorporation of rebel forces into the Syrian army.

As Assad, and his Russian backer, continue to gain ground, diplomatically and on the battlefield, both sides in Syria are waiting to for a clear signal from new US President Donald Trump, who has promised to build closer ties to Russia and focus US actions in Syria on fighting ISIL.

De Mistura warned over the weekend that while US policy on the crisis remains in disarray, there would be no chance of any major breakthroughs in forging a political solution in Syria.

The executive director of Human Rights Watch, Kenneth Roth, seconded de Mistura's warning, saying that delayed diplomacy could have serious repercussions for the Syrian people.

"God help the Syrian people, if we are waiting for Donald Trump to provide the solution," he said. "It is incumbent on all of us to step forward while the US is in disarray."