This past weekend, Jabhat al-Nusra made sweeping gains in Idlib province, taking key towns and villages controlled by two U.S.-backed rebel groups: The Syrian Revolutionaries Front and Harakat al-Hazm. They routed the groups from their strongholds and forced them to either “flee or defect.”

The offensive prompted U.S. officials to consider broadening the air campaign in Syria to strike Jabhat al-Nusra. Besides one attack by Tomahawk missiles in late September, the U.S.-led coalition has made it clear that its primary target in Iraq and Syria is ISIS.

“The strike ‘put inter-rebel relations under enormous strain,” says Faysal Itani, a fellow at the Atlantic Council.

*‘By striking Jabhat al-Nusra without sufficiently strengthening its moderate counterparts first and promising (publicly, no less) to use them to fight Jabhat al-Nusra and not the regime, the United States made the opposition appear just threatening enough to provoke Jabhat al-Nusra, but not so threatening as to deter the jihadist group,” Itani writes in a new Atlantic Council report.*

Jabhat al-Nusra’s leader, Abu Mohammad al-Golani, said that his fighters intend to eliminate the Syria Revolutionaries’ Front (SRF) and released a video message saying the ‘’so-called moderate (Syrian) factions are better called (Western) collaborators.”

As it now stands – the Western-backed opposition is fighting three battles: one against the Assad regime, another against ISIS, and a third against Jabhat al-Nusra.

Itani spoke to Syria Deeply about the shift in dynamics and its consequences on Syria’s war.

Syria Deeply: What do we need to know about Jabhat al-Nusra and what’s happening in Syria now?

Itani:Jabhat al-Nusra has appeared to move against two factions that are closely aligned with the U.S: Syrian Revolutionaries Front and Harakat al-Hazm. They’ve done that in territory where supposedly these two factions were pretty safe and on comfortable ground. They’ve pretty much displaced them from the area. It doesn’t appear that the aim was to destroy these groups, but really just to take territory. There are reports that several hundred members of the Syrian Revolutionaries Front and Harakat al-Hazm have defected to Jabhat al-Nusra.

Syria Deeply:How have recent advances by Jabhat al-Nusra changed the dynamics on the ground, potentially weakening the U.S.-backed Syrian opposition?

Itani:The fact that the groups got routed in territory where they are from is pretty disastrous. We are crossing a milestone in terms of inter-rebel dynamics. They are now in open conflict. I don’t see it as yet entering an all-out war: there will be local understandings, truces, there might be some cooperation between Jabhat al-Nusra and other groups, but not the SRF and Harakat al-Hazm. It’s out in the open now that U.S. strategy has placed these insurgent groups in an impossible position vis a vis Jabhat al-Nusra.

Syria Deeply:Why did Jabhat al-Nusra go after SRF in particular?

Itani:This is an opportunistic and preventive move by Jabhat al-Nusra. What I assume is that Jabhat al-Nusra has calculated that these groups are aligned with their enemy and that this alignment won’t shift. Additionally, if the U.S. has its way, it will deploy these insurgent groups against Jabhat al-Nusra in some capacity further down the line. Nusra obviously calculated that these groups are not powerful enough at this moment to resist an offensive in territory that is important to them.

These are important geographies – they are fighting supplies lines, areas adjacent to Aleppo, which is still up for grabs between ISIS, Nusra and the regime.

The SRF and Harakat al-Hazm have been given some of what they’ve asked for in terms of small arms, but they haven’t been given enough supplies to attract recruits and build up a strong enough position within the insurgency itself.

It’s not just a question of whether they have enough ammunition to fight Jabhat al-Nusra; it’s a question of their stature more broadly within the insurgency.

The fact is that the U.S. has not supplied them robustly, but in terms of a public diplomacy position we’ve put them in a very hard place.

The U.S. has essentially told these groups that they are not part of the U.S. air campaign in Syria, that it won’t help them fight the regime, and that they explicitly intend for the groups to fight Jabhat al-Nusra.

The U.S. hasn’t involved them at this stage in the planning, intelligence sharing and the military execution of the campaign. It’s not just about just money and weapons. It’s about the perception of these groups standing among Syrians and their ability to deliver, protect their fighters and fight the regime.

The U.S. didn’t position them to deal with the fallout of the air campaign, and now we are losing them.

Syria Deeply: What are the implications of rebel groups defecting to join Jabhat al-Nusra? Why is it happening?

Itani: We are going to see the position of the more moderate groups erode even further than it has in the past two years. There are also implications for U.S. policy, which is that the result of the air campaign and the way it’s been conceptualized and carried out is that our ostensible partners in Syria are being destroyed and Jabhat al-Nusra has been empowered, particularly if they can attract recruits.

Essentially it’s produced the exact opposite results of what the U.S. claims it wants to pursue.

Syria Deeply: Moderate rebel groups in Syria are under growing pressure as Assad forces an advance on the country’s west and south, while ISIS makes gains in the east and north. What are the implications of Jabhat al-Nusra successfully taking key battleground in the northwest?

Itani:Nusra has been encroaching on Idlib for a few months now. Harakat al-Hazm and SRF are a couple of the very few allies that the U.S. can call its direct allies, in the sense that the U.S. openly and explicitly supported them. If the terrain in Idlib is lost to Nusra, the areas where the U.S. has partners are limited to the south – Qunietra and Deraa provinces – and certain pockets of rebel territory around Damascus. The options of the U.S. contract considerably and it loses key geography in the country.

Syria Deeply: From a strategic perspective, how has Jabhat al-Nusra been gaining ground and gaining influence?

Itani:The reason Nusra has been interesting from the beginning is that it is building inroads into and establishing itself among the Sunni-Arab population of the country. There has always been a question of what direction Jabhat al-Nusra would go in and who would define what Sunni-Arab politics in Syria would be about. Because the situation militarily is so fluid and because the country is politically undergoing a transformation, if this becomes the political orientation of a large group of Sunni Arabs in Syria, the long-term political trajectory of the country is profoundly effected, even if the Assad regime is or isn’t defeated. If these are the champions of the Sunni-Arab cause in Syria, an al-Qaida offshoot, then there is reason to be worried.

Photo Credit: Courtesy of AP Images