Members of al Qaeda's Nusra Front are seen in May 2015 in Ariha, in Syria’s Idlib provinceAmmar Abdullah / Reuters

In the fall of 2016, Syrian troops loyal to Bashar al-Assad, backed by Russian airstrikes and Iran-backed militias, marched on Aleppo and ultimately captured the city of 200,000 people, leaving a trail of destruction and human suffering. In February of this year, they besieged Eastern Ghouta, a region outside Damascus, and bombed it into submission, again leaving accounts of suffering in the area of 400,000 people. Meanwhile, the death toll continues to climb—the most widely cited estimate puts the lives lost at half a million, though there’s no way to know for sure; the UN stopped counting years ago. Yet Syria’s already horrific battles, and the human suffering they’ve caused, may pale compared to what comes next: Assad’s forces, backed by Russian airstrikes, are surrounding Idlib, in northwest Syria, preparing for an onslaught against the last major rebel-held area. Population: 3 million.

The International Crisis Group, a conflict-monitoring organization,  says about one-third of the civilians in Idlib fled other conflict zones in Syria. The UN estimates that the fighting could displace up to 800,000 people who have nowhere to go. Turkey, which shares a border with the region, already hosts some 3.5 million Syrian refugees, more than any other country in the world. Confronted with growing domestic frustration at the refugees and an economy that has turned sour, Ankara has closed its border with Syria.

“This is going to be far more catastrophic than anything we witnessed so far” in the Syrian conflict, Mona Yaoubian, an expert on Syria at the U.S. Institute of Peace, told me. She said the large numbers of civilians and the fact that there’s nowhere for them to go makes the impending fighting a particular risk for civilians. “I think by all accounts, the regime is going to stop at nothing to take this territory back,” she said. “And so we expect a particularly brutal onslaught on the part of the Syrian regime backed by the Russians”

Andrew Tabler, who is an expert on Syria at the Washington Institute, told me it’s important to watch for how the assault proceeds: “Does it just focus on certain road arteries? Does it push beyond that? That’s where it becomes very difficult. Because you have about 3 million people living in Idlib, and you have a lot of extremists in that area as well.”

Russia’s Defense Ministry said Wednesday that its warplanes had bombed targets belonging to al-Nusra, the former al-Qaeda affiliate that is now part of Hayat Tahrir al-Sham, a coalition of Islamist groups, in Idlib on Tuesday. They did not target civilian areas, the ministry said—though the Russians in the past have claimed that the civilians they killed in Syria were terrorists. Indeed, those civilian areas are likely to be discussed this Friday when the leaders of Russia, Iran, and Turkey will meet in Iran to, in the words of the Kremlin, “further joint efforts to ensure long-term normalization of the situation in Syria.” The U.S. is not part of this process.

The Russia airstrike came days after a back-and-forth between President Donald Trump and Russia’s foreign ministry. The American president tweeted on Sunday that Assad “must not recklessly attack Idlib Province,” warning that it would be a “grave humanitarian mistake.” Trump, whose skepticism of U.S. military involvement overseas is well-documented through his comments and tweets, has previously not shied away from using force when confronted with images of human suffering from Syria: The U.S. struck targets in the country following Assad’s use of chemical weapons in April 2017 and April 2018.

Dmitry Peskov, the Kremlin’s spokesman, dismissed Trump’s tweet, however: “Just to speak out with some warnings, without taking into account the very dangerous, negative potential for the whole situation in Syria, is probably not a full, comprehensive approach,” he said.

Assad and Syria maintain that they are fighting terrorists. Indeed, among the many rebel groups that operate in Idlib is HTS, the alliance that is led by the former al-Qaeda affiliate in Syria. It is almost certain that when Russia and Assad talk about terrorists, they mean HTS, but they’ve also appended this label to any group fighting the Assad regime. Indeed, Assad and his allies have rarely discriminated between Islamists and moderate groups when unleashing the weapons of war on rebel-held areas with large civilian populations. On Tuesday, Mike Pompeo, the U.S. secretary of state, told reporters that while he shared Russia’s concerns about “terrorism emanating from northern, northwest Syria … [who] need to be taken care of … We are hoping that this can be resolved diplomatically."

“It is not the way to do that to put the lives of all these innocent civilians at risk and create a humanitarian crisis,” he said. “We’re always concerned they may use chemical weapons in the process of trying to obtain their military objective.”

The U.S. military role is limited in Syria. About 2,000 U.S. troops are embedded with Kurdish fighters in the north of the country, and operate exclusively against ISIS. The U.S. continues to provide reconstruction aid and other incentives despite having cut some aid. Tabler argued that Trump’s tweets on Sunday showed that the U.S. is not giving up in Syria.

“The U.S. has influence over the situation, but does not have absolute leverage,” he said. “It’s hard to influence the outcome of a war unless you’re willing to use military force. The big difference with this administration [over the previous one] is that it is willing to use pinpointed military force, particularly for chemical weapons.”

Russia, despite evidence to the contrary, denies that Assad’s forces have used chemical weapons against rebels and civilians. It has also dismissed speculation that there are plans afoot to use chemical weapons in Idlib. But even without such weapons, Russia and Assad have used conventional weapons to inflict untold suffering across Syria. Many of those operations, including the battle for Aleppo and Eastern Ghouta, took months. Idlib is expected to be no different.

“Seizing Idlib is not going to be easy,” Yacoubian said. “There are an estimated 70,000 rebels on the ground who are not going to give up easily ... These are folks that are far less willing to negotiate or have sort of surrender. So they’re going to fight to the end.”

Assad’s eventual victory in Idlib is by no means a sign that the more than seven-year-long Syrian civil war is at an end. At best, it can be said that he has defeated the armed rebellion, but the conflict in Syria has now metastasized into a regional proxy war, involving Iran, Turkey, Russia, and others.

As Yacoubian told me: “This is the last remaining rebel stronghold in Syria. So its fall does, in many ways, signal the death knell for the organized territory-holding aspect of the anti-Assad armed opposition.” But, she said, because of the other actors now involved in Syria, “there are other conflicts that will continue.”

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