A newly agreed ceasefire in Idlib, Syria's last opposition stronghold, could offer a welcomed respite for the province’s desperate civilian population. But if the agreement doesn't hold, its collapse could usher in the worst humanitarian chapter of the 8-year conflict.
The big picture: The Syrian government announced the ceasefire shortly after UN Secretary-General António Guterres authorized an investigation — requested by a majority of the Security Council — into the Syrian and Russian bombing of hospitals and schools in Idlib. The terms pause the Assad regime's offensive in exchange for a 20-kilometer (12.4-mile) withdrawal by opposition fighters.
Where it stands: Some 3 million people are sheltering in Idlib. Extensive Russian-Syrian bombardment has killed hundreds, injured thousands, and displaced some 440,000 people.
In just 3 months, the regime's offensive has led to the war's single largest mass displacement, while humanitarians lack access to the city and resources to respond.
Background: The demand for a rebel withdrawal is in line with the agreement reached in Sochi, Russia, last September.
Under Sochi, Turkey was responsible for — but failed to deliver — the rebel withdrawal. The deal collapsed in April when the Assad regime launched an assault on Idlib, backed by a Russian bombing campaign.
To date, Assad’s troops have made little progress against the rebels, including the al-Qaeda–linked militants and other jihadi groups that dominate Idlib province.
Between the lines: In agreeing to the ceasefire, Moscow and Damascus may be responding to both renewed UN scrutiny and military realities on the ground. The regime has used past ceasefires to resupply troops and prepare for subsequent offensives.
What's next: No timeline has been set for the withdrawal of opposition fighters. There is little reason to believe the rebels will meet that demand, which was also a central condition of the Sochi agreement. Indeed, Assad used their refusal to leave demilitarized zones to justify the recent offensive.
The ceasefire comes amid talks to plan a new constitutional committee — sponsored by Russia and held in Kazakhstan — among the Syrian government, the opposition, Iran and Turkey.
Unless Turkey can compel the rebels to withdraw, fighting will likely resume. If it does, the UN warns that the unfolding humanitarian crisis could be the worst of the 21st century.