Istanbul

After seven years of war, the deaths of as many as 400,000 civilians, and the displacement of half its population, Syria entered a new phase of the conflict on Monday that some analysts see as a major step toward ending the bloodshed.

First the military development: Rebel forces, including Islamist radicals, have pulled their tanks and heavy artillery away from the provincial borders of their last stronghold, in Idlib, the northern province packed with 3 million people, half of them displaced from other regions of Syria.

The context for the withdrawals was a political deal between Turkey and Russia, under which both powers became guarantors of the security of the province. Turkish forces will patrol from a dozen newly fortified observation posts on the Idlib side of the provincial border and Russia from 10 posts on the Assad-regime side.

The agreement reached on September 17 by Turkish President Recep Tayyip Erdogan and his Russian counterpart, Vladimir Putin, required the withdrawal of heavy weapons by Monday, and now a 10-mile-wide heavy-weapons exclusion zone on the Idlib side appears to be in place.

Internationally labeled terror groups, including Hayat Tahrir al-Sham (HTS), the successor to the Al Qaeda–linked Jabhat al-Nusra, were among those complying. “The terrorist-designated groups withdrew their weapons from the DMZ,” said Col. Fateh Hassoun, the rebel forces’ representative in negotiations among Turkey, Russia, and Iran known as the Astana process. He said at least 100 pieces of equipment were withdrawn, two-thirds of them belonging to the National Liberation Front, an umbrella group for moderate rebels, and one-third from HTS. Now security is in Turkish hands.

“There isn’t any guarantee that the regime will not spoil this agreement, except for Russian guarantees, which are not better than the regime’s,” Hassoun said. “However, our real guarantee is Turkey and the fact that there is the agreement. Add to this that Turkey is enhancing its military buildup in the area, and its political and military leadership say they will protect it.”

Not every rebel group is celebrating. “To be honest, our opinion isn’t important. Things are progressing whether we like it or not,” said a spokesman for one group who asked not to be identified by name.

But Ahmed Toma, the opposition’s political representative at the Astana talks, called the agreement a step in the right direction. Idlib “has become safe in every sense of the word,” he said. “Now we hope it will pave the way to a political solution” under international auspices, not those of the regime.

The International Crisis Group, an independent NGO that closely monitors wars, agrees. Last month, following the Sochi agreement, it switched its symbols depicting the trends in the Syrian war to “improved” from “deteriorated,” and even referred to “resolution opportunities.”

“Sochi does forestall an attack on Idlib that would be a humanitarian disaster with far-reaching consequences for Syria and beyond,” said Sam Heller, the ICG analyst for Syria. But, because the accord flowed from the Astana talks, “it’s possible it could yield additional progress toward an agreement.”

Turkey is no doubt the outside player that pushed the hardest for removing the threat to Idlib, but other powers contributed to the outcome, including the Trump administration.

Erdogan publicly warned that an offensive would have enormous humanitarian consequences for Turkey’s national security; a large outflow of refugees would have major repercussions for Europe as well. He publicly called for a complete cease-fire, but Turkey’s behind-the-scenes role may have made the bigger difference. It encouraged moderate rebel forces, estimated at up to 100,000, to unite and prepare to fend off an offensive. (HTS has some 10,000 fighters, half of them foreign, and the breakaway Al Qaeda faction, Hurras ad-Din, has a few hundred, according to close observers.)

“That may not have been enough to repel an attack and ultimately win, but it was potent enough to make any victory by the Syrian government extremely costly,” said the ICG’s Heller. Erdogan also made clear that a regime offensive with Russian backing would have a negative impact on Ankara’s relations with Moscow and would lead to a Turkish withdrawal from the Russian-sponsored Astana process.

The most important Turkish move, which received the least publicity, was its decision to engage in secret talks with HTS leader Abu Mohammad al-Jolani—first to open the way for Turkey to set up its border observation posts and send in Turkish forces, then to withdraw HTS forces from the demilitarized zone. The final step Turkey hopes to achieve is to dissolve or contain HTS. There was no sign of that happening as of Monday. Indeed, HTS issued a statement, its first since the Sochi agreement, saying it would not remove its heavy weapons from the DMZ nor would it stop fighting until the overthrow of the Syrian regime. “HTS complied with the agreement without saying so openly,” said a media activist in Hama, who asked not to be identified by name. “They told their fighters they had to relocate their heavy weapons lest they be bombed. The fighters have no idea about the Sochi agreement.”

The new player on the scene was the United States, which had confined itself under the Trump administration to two symbolic air assaults after the Syrian regime used chemical weapons against civilians, and a continued presence in eastern Syria to fight ISIS.

Last March Trump called for the earliest possible departure of US Special Operations forces from eastern Syria, where they’d been directing a Kurdish-led ground force in the fight against the remnants of the Islamic State. But in August, Trump appointed a skilled diplomatic team—James Jeffrey, the former ambassador to Turkey and Iraq, and Joel Rayburn, a former Army intelligence officer and current deputy assistant secretary of state.

The mission of the 2,000-odd US forces has since been modified, Secretary of State Mike Pompeo said last week; it now includes a peaceful political resolution of the Syrian conflict and the removal of all Iranian and Iranian-backed militias. But removing the Iranian-backed militias would cut away one of the prime pillars of support from the Assad regime.

Washington’s policy in the region, criticized bitterly by NATO ally Turkey and other regional players, has had unintended consequences that may have helped bring the Sochi agreement about. According to Ahmed Toma of the Syrian opposition, Trump’s decision to impose sanctions on Iran strengthened Erdogan’s hands in the negotiations with Russia and Iran. That’s because Turkey, which depends on Iran for its natural-gas supplies, has declared that it will not observe the US sanctions that come into effect next month, and Iran is counting on Turkey. “Do you think Iran wants to anger Turkey, a neighboring state that it will need to ease the effects of siege and sanctions on Iran?” he asked.

Iran, which had supported the Lebanese Hezbollah, Iraqi, and Afghan militias that have been defending the Assad regime and recapturing territory from rebels, didn’t deploy those forces to intervene in Idlib but urged the Tigers, one of the Syrian army’s most effective units, to withdraw from the Idlib border, Toma said. In making that decision, the US role “may have been salient for Iran,” said the ICG’s Heller.

Another US policy under continued heavy criticism from Turkey is the support since 2014 of the Kurdish People’s Protection Units, or YPG, the Syrian affiliate of the banned Kurdistan Workers’ Party, or PKK, in the fight against ISIS. The unintended consequence of the contentious US policy is that YPG fighters, who have a history of close ties to the Assad regime, were preoccupied with the battle against ISIS and were not in a position to volunteer to fight in Idlib.

In fact, every player had its reason for not going forward with the Idlib offensive.

The Assad regime, which announced the Idlib offensive but could not muster enough of its own forces to carry it out, is the potential spoiler of the stand-down. But if it makes threatening moves or restarts the war, it will be under the spotlight and face immediate pressure from Turkey, the United States, and possibly other players to back off.

Iran’s public statements indicate that it is adamantly opposed to an operation in Idlib. Jaberi Ansari, a senior foreign-ministry official, told Iran’s Press TV last week that the presence of a large civilian population, and of a “terrorist group” mixed in with them made a quick fix impossible. He called Idlib “the epitome of the complexities of the Syrian conflict.”

And Russia has reasons to avoid a bombing campaign in Idlib, for Turkey and European countries would pile on the criticism due to the humanitarian impact of such a campaign. Russia is already under strong criticism for bombing operations in the three years since Putin ordered the intervention. The Syrian Network for Human Rights says in a new report that Russian forces have killed 6,239 civilians, including 1,804 children, since the start of their Syrian military campaign in the fall of 2015. It said Russian forces had carried out 176 attacks on schools, 166 attacks on medical facilities, and 55 attacks on markets. The SNHR, whose data have been cited in annual State Department human-rights reviews, said Russian operations have violated UN Security Council resolutions demanding an end to indiscriminate attacks and that its operations constitute war crimes and crimes against humanity.

Will the Idlib stand-down and the constellation of major players that brought it about last long enough for statesmen to revive the moribund peace process? As the Crisis Group put it, the opportunity is there. .