At midnight on February 27, the guns fell silent in Syria—at least temporarily. With numerous allegations of breaches beginning to surface, Syria’s ceasefire is already on shaky ground. This cessation of hostilities, as it is formally called, followed two weeks of intensive negotiations between the United States and Russia. Just before the clock struck twelve, their efforts reached fruition when the UN Security Council unanimously approved resolution 2268, endorsing a Russian-American agreement from February 22 and demanding that Syrian and international actors comply.

But will they? And with what exactly do they need to comply? In addition to the disparate motivations of outside actors, the complex calculations and relations among Syrian jihadi and non-jihadi rebel factions make this a perilous process.

How Did This Happen?

The most important thing to understand is that this cessation is not an indigenously-led process. If left to their own devices, the warring parties in Syria would still be killing each other—and many civilians too—while scoffing contemptuously at any talk of peace. Neither is it truly a regional deal. It is essentially a bilateral understanding between Washington and Moscow that has either been supported by or rammed down the throats of their regional allies, which are in turn expected to bring their Syrian clients into the deal.

When the Geneva III talks were suspended in early February, as a result of a Russian- and Iranian-backed breakthrough for Syrian President Bashar al-Assad’s forces in Aleppo, international diplomacy went into overdrive to avoid a complete collapse of the peace process. The United States had invested heavily in the Geneva process and the Russian government presumably also had its reasons to get the talks back on track.

This produced a new agreement underwritten by the International Syria Support Group (ISSG), a recently-created gathering of states involved in the Syrian peace process. In this agreement, Moscow and Washington named themselves the joint heads of an ISSG Ceasefire Task Force, momentarily brushing their unruly allies aside in order to sit down, mano a mano, and talk like adults. The result was the February 22 agreement, which mandated a cessation of hostilities on February 27. A technical annex to the deal explains that Moscow and Washington will be responsible for managing the process by dealing with their ISSG allies, sharing information, mapping out protected areas, and adjudicating disputes. They will do so through two monitoring centers: a Russian one set up at the Hmeymim Airbase near Latakia in Syria, and an American one in Amman, Jordan.

The warring parties were then told to sign on to the terms of the deal, take it or leave it. If they failed to do so, they would be considered fair game for all sides once the agreement entered into force.

Who Is Included in the Deal?

Groups listed as terrorists by the UN Security Council were automatically excluded. They include the self-proclaimed Islamic State, the al-Qaeda-aligned Nusra Front, and a few other small organizations and individuals on the jihadi fringes of Syria’s Sunni insurgency. Of course, given their politics, these groups were never going to abide by the deal anyway. The Nusra Front leader Abu Mohammed al-Golani has made an angry statement calling for more war, and while the Islamic State has not yet presented its position, the world is not exactly waiting with bated breath.

All other groups had the option of signing up or not by contacting the monitoring centers. Most of them did, including the Assad government, the Kurdish-led Syrian Democratic Forces militia, and most of Syria’s non-jihadi rebels.

The High Negotiations Committee (HNC), which was elected at an opposition conference in Riyadh last December, represented most of the non-jihadi rebels. In all, some 70 rebel factions allowed the HNC to sign on to the ceasefire on their behalf. An Arabic-language list of those reported to be among them can be found here. It includes nearly all of the main groups backed by the United States, Saudi Arabia, France, Qatar, Turkey, and the other states in the so-called Friends of Syria camp that has sought to depose Assad since 2011.

These rebel factions typically refer to themselves as members of the Free Syrian Army (FSA), which is more of a loose umbrella term than an actual organization. In fact, the December 2015 Riyadh Conference did much to clarify who does and does not belong to this bloc. Even the hawkish Islamist faction known as the Islam Army has now fallen into line and agreed to issue statements under the FSA label; it too was among the factions that approved the cessation of hostilities through the HNC.

What about Ahrar al-Sham?

Questions remain regarding the position of the powerful Qatari- and Turkish-backed Islamist group Ahrar al-Sham. After some confusion, the group withdrew from the Riyadh conference and therefore does not fall under the HNC umbrella. While the group has maintained public silence, some claim that Ahrar al-Sham has in fact added its name to the list of factions that signed up through the HNC, but it is not clear whether that represents the entire movement. Sources close to the group claim that its leadership simply could not bring itself to decide one way or the other because internal divisions proved too severe.

For Ahrar al-Sham and Islamists of that stripe, the main problem with the deal is not that it winds down the fighting. Rather, it is that the deal explicitly targets the Nusra Front, which is Ahrar al-Sham’s most important military ally, although it is also, in some respects, a political rival. Given the Nusra Front’s intransigent attitude, endorsing the deal could provoke a fraternal war among the Islamists and split Ahrar al-Sham. That could in turn catastrophically undermine the opposition’s already-faltering military defenses. Many Syrian Islamists therefore view the cessation of hostilities as a way for the international community to drive a wedge between Syria’s most powerful anti-Assad factions. They are not necessarily wrong.

Even though Ahrar al-Sham has refused to follow the Nusra Front in condemning the deal and the Americans seem to think that they have secured its approval, several of the group’s best-known leaders have now publicly voiced their opposition. They include notable hardliners such as the former Sharia chief Abu Mohammed al-Sadeq and the head of the military wing, Abu Saleh Tahhan, as well as Abu Azzam al-Ansari, who is viewed as a relative moderate. The well-known Ahrar al-Sham dove Hussam Salameh has hinted that with or without a formal signature, his group will not seek to derail the deal, which sounds like a practical kind of live and let live arrangement. But in a later interview, following a fresh round of Russian airstrikes, Salameh dismissed the agreement as “stillborn,” saying there is no consensus about its terms.

For now, the lack of clarity seems to work in favor of the deal. But if worse comes to worse and Ahrar al-Sham decides to team up with the Nusra Front to rekindle the fighting, it will be impossible to keep the peace.

The Jihadi Problem

War against the Islamic State is not necessarily disruptive for the rest of Syria, as its territory is fairly well delineated from other factions and it has no allies who could take offense.

The Nusra Front, however, is another matter entirely. It is deeply embedded within the Sunni Islamist landscape, particularly in northern Syria. Russian, Syrian, and American airstrikes that target the group often end up hitting other factions as well, not to mention civilians. These attacks always meet with howls of protest from the broader opposition, often including factions backed by the United States.

In addition, Russia, the Assad government, and the Kurdish militias have all made a habit of indiscriminately labeling anything they attack a Nusra Front or Islamic State target. Sometimes that is true, but they do so even when they know it is not. If they decide to treat Ahrar al-Sham as an outlaw faction on par with the Nusra Front, they will find themselves with a smorgasbord of internationally-approved targets. In that case, there is no way the truce could last. To make matters even worse, the Nusra Front, or factions of it, may seek to undermine the deal by staging provocative attacks that they know will draw retaliatory fire against other rebels.

In other words, the commingling of mainstream and jihadi factions in rebel-held Syria is not merely a small problem with the design of the February 27 cessation of hostilities; it is a loophole through which one could drive a Sukhoi-35.

If this deal is to work as intended, Russians, Americans, Kurds, and others will all have to show significant goodwill and decline to exploit its ambiguities in their own favor. For lack of better options, the Americans seem profoundly committed to see this plan through and can perhaps be expected to do that. But what about Bashar al-Assad, Hezbollah, or Ahrar al-Sham? What about Recep Tayyip Erdogan’s Turkey, King Salman’s Saudi Arabia, or Vladimir Putin’s Russia? The past five years give little reason to hope for that kind of Kumbaya moment in Syria.

Has the Violence Stopped?

“Violence has not stopped, but it has plummeted,” wrote Maya Gebeily, a journalist with Agence France-Presse in Beirut who covers the Syrian war, on February 29. According to a Western diplomat citing UN envoy Staffan de Mistura, the number of airstrikes has dropped from 100 to about 6 or 8 per day. If those numbers are true, and stay true, it is amazing progress.

Indeed, with the exception of a brutal Islamic State raid on Kurdish-held Tal Abyad, fighting seems to have diminished considerably since February 27. It is perhaps partly a result of Russia’s decision to suspend air raids on the first day of the cessation of hostilities. This rare goodwill gesture seems to have done much to get the deal off the ground. But the opposition speaks of systematic violations by Assad and Putin, 15 times in the first day and more after the resumption of Russian bombings. The Syrian government has also complained of shelling and other violations by rebels.

The problem is, of course, that no one really knows what constitutes a violation as there is no agreement on which areas are under terrorist control. The way the system was set up in the February 22 deal is that transgressions are to be reported to ISSG members. The American and Russian task force will then decide on a proper course of action, whether it be some form of pressure on the guilty party or a public warning. In theory, offenders could be stripped of their protected status or even targeted by airstrikes. But such punishment would never be meted out against Assad, as doing so would end the deal, or against the SDF, as the Kurds are allied to both the United States and Russia. In practice, only out-of-control rebel groups and perhaps some small and seriously wayward pro-government militias are at real risk of ending up on the UN-approved kill list.

For now, no such measures seem to be under consideration—implementation of the deal is just getting started—although some breaches are clearly being committed. The Amman center has not issued any public statements, but ISSG member France has said that attacks are still targeting “zones controlled by the moderate opposition.” And on Sunday, Russia’s monitoring center in Latakia claimed to have registered nine violations by the opposition or its backers, including Turkish cross-border shelling of Kurdish positions in Tal Abyad.

What Happens Now?

In the coming days, the United States and Russia have their work cut out for them: managing inevitable crises and conflicts, reining in their allies, and trying to win the media war.  The immediate goal will be to safeguard the deal until the Geneva III talks can resume, tentatively scheduled for March 7. Around that date, UN Secretary General Ban Ki-moon is also expected to hand in a progress report to the Security Council and, soon after, the cessation of hostilities will need to be formally extended.

The hope seems to be that muddling along in this way will result in a long series of extensions. By winding down the violence and encouraging the jihadi irreconcilables to isolate themselves from a deal that enjoys widespread popular support, the ISSG co-chairs hope to create the appropriate environment for a more comprehensive ceasefire, and perhaps even some political discussions further ahead. Unless it all goes up in flames first.