A boy inspects his school, which activists say was damaged in an airstrike carried out by the Russian air force in the Syrian town of Injara, in Aleppo province, on Jan. 12, 2016. (Khalil Ashawi/Reuters)

Russia’s military intervention in Syria is finally generating gains on the ground for Syrian government forces, tilting the battlefield in favor of President Bashar al-Assad to such an extent that the Obama administration’s quest for a negotiated settlement to the war suddenly looks a lot less likely to succeed.

The gains are small-scale, hard-won and in terms of territory overall don’t add up to much, in keeping with the incremental nature of war.

But after 3½ months of relentless airstrikes that have mostly targeted the Western-backed opposition to Assad’s rule, they have proved sufficient to push beyond doubt any likelihood that Assad will be removed from power by the nearly five-year-old revolt against his rule. The gains on the ground are also calling into question whether there can be meaningful negotiations to end a conflict Assad and his allies now seem convinced they can win.

“The situation on the ground in Syria is definitely not conducive to negotiations right now,” said Lina Khatib of the Paris-based Arab Reform Initiative think tank.

Peace talks scheduled to start in Geneva next week are already in doubt because of disputes between Russia and the United States, their chief sponsors, over who should be invited.

The alliance between Russia and the regime of Bashar al-Assad goes back decades. Here's a bit of historical context that explains why Russia is fighting to prop up its closest ally in the Middle East. (Ishaan Tharoor and Jason Aldag/The Washington Post)

Russia and the Syrian government are objecting to a U.S.-backed list of opposition delegates drawn up in the Saudi Arabian capital of Riyadh last month that includes representatives of some of the main rebel groups, saying that they won’t negotiate with people they term “terrorists.” Russia is pushing instead for the inclusion of a group of government-approved opposition figures who have remained loyal to Assad and also of Syria’s Kurds, who are fighting a somewhat different war on their own behalf in northeastern Syria.

[Is it too late to solve the mess in the Middle East?]

U.N. spokesman Farhan Haq told reporters in New York on Monday that the U.N. Special Envoy for Syria, Staffan de Mistura, would not issue invitations to the talks until Russia and the United States agree on who should represent the opposition. He did not rule out that there could be “slippage” on the Jan. 25 date.

U.S. Secretary of State John F. Kerry and Russian Foreign Minister Sergei Lavrov are expected to try to hammer out the differences at a meeting Wednesday in Zurich, five days before the scheduled start of the talks.

Even if the guest list is agreed upon, however, it is far from clear whether the opposition will attend without some gesture on the part of Russia and Syria to demonstrate that they are negotiating in good faith. A group of 33 rebel groups issued a statement last week saying they would not join the talks unless Russian and Syrian warplanes stop striking civilian targets, release political prisoners and send humanitarian aid to besieged towns such as Madaya, where people have been dying of starvation.

[23 people starve to death in besieged Syrian town, medical charity says]

The opposition is also seeking clarity on the agenda of the talks, which are officially supposed to conform to a formula drawn up by Russia and the United States in Geneva in 2012, at a time when the rebels appeared to be winning, and was more recently were endorsed by a gathering of world powers in Vienna late last year.

The Geneva process never clearly stipulated that Assad should relinquish power, but the opposition and the United States said they thought that was the intended goal.

Nearly four years later, with Syrian troops and their allies gaining ground on multiple fronts in the north, the south and the center of the country with the support of Russian airstrikes, there is no longer any reason for Assad to feel pressure to step down, and the United States has pulled back from its insistence that he do so.

Nor is there any reason to think that either the government or the Russians will be willing to make concessions, whether before or during negotiations, analysts say.

Rather, Khatib said, it appears that both the Russians and the Syrian government are intent on buying time in order to continue to grind down the opposition.

“Russia’s strategy is to weaken the Syrian opposition to the point of elimination, so that in the future Russia may well be able to argue that there is no one to negotiate with,” she said.

If the talks don’t take place anytime soon, it will be a serious setback for a key goal of the Obama administration’s foreign policy. With the Iran nuclear deal now in the implementation phase, putting an end to the bloodshed in Syria has emerged as one of the Obama administration’s top priorities.

U.S. officials say they recognize that other foreign policy goals, including the defeat of the Islamic State and halting the flow of refugees from Syria, cannot be fulfilled without ending the war, which is thought to have claimed in excess of 250,000 lives and displaced more than 11 million people so far.

[How the battle against the Islamic State is redrawing the Middle East map]

Instead, it seems likely that the killing will continue, with pro-government forces seeking to capitalize on the steady weakening of rebel forces.

The Russian intervention got off to a rocky start last October, with initial attempts by Syrian government forces to advance under Russian air cover stalled by an onslaught of dozens of antitank missiles that had been supplied to U.S.-vetted groups by the United States and its Arab allies. The intervention came after gains by rebel forces had called into question Assad’s ability to survive, and seemed intended to reinforce his increasingly shaky hold on power.

To that extent, the airstrikes have worked. The supply of the missiles has since slowed down, rebel fighters say, as the intensity of the airstrikes has steadily increased. The targeting by Russian warplanes of supply lines from Turkey has impeded access to weapons as well as food and humanitarian supplies, according to the rebels.

At the same time, Syrian troops have advanced on several key fronts. After driving the rebels out of a string of villages near the Turkish border in northern Latakia province, last week they recaptured the town of Salma, which had been in rebel hands for nearly three years. Syrian troops have been making advances in and around the key city of Aleppo and have begun to pressure the rebels in some of their strongholds in southern Syria.

Even if the talks do take place, it is hard to see how they could progress toward a meaningful solution when the balance of power on the ground and in the diplomatic arena has shifted so decisively in favor of Assad and his allies, said Jeff White, a military analyst at the Washington Institute for Near East Policy.

“Under the current military circumstances, there is no reason for the strong alliance to go and negotiate a win-win solution. The stronger alliance is going to go into the negotiations and dictate terms,” he said.

“Either the negotiations will fail because the opposition forces that are there will refuse to become part of a surrender-type solution, or the people on the ground will just say, fine, and continue to fight,” he added.

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