President Obama’s speech last week signaled a likely expansion into Syria of American airstrikes against the Islamic State in Iraq and Syria, yet offered little indication of an immediate strategy to halt ISIS’ gains there. The administration’s first focus thus remains on Iraq, while familiar pledges to work with regional allies and increase support to moderate rebels in Syria — if Congress approves sufficient funding — appear divorced from the urgency of the situation on the ground.
Though Western attention is drawn to Iraq, it is Syria that has witnessed the most significant ISIS gains since June. It is Aleppo, Syria’s largest metropolitan area, that presents ISIS’ best opportunity for expanding its claimed caliphate. An effective strategy for halting, and eventually reversing, ISIS’ expansion should begin there, and soon.
Stopping ISIS requires addressing the problems that enabled its rise. Among other factors, like lax Turkish border controls, ISIS has profited from the sectarian politics and indiscriminate military tactics of autocrats in Baghdad and Damascus. With Iranian support, these leaders have worked systematically to prevent the emergence of credible, moderate Sunni alternatives.
The Syrian opposition’s Western and regional allies have inadvertently aided that effort, as their blend of tough talk and weak, poorly coordinated support has undermined the Syrian rebels whom, ostensibly, they back. ISIS has exploited the resulting vulnerabilities among its Sunni competitors by combining the allure of empowerment to those who join with the threat of brutal punishment to any who resist.
These dynamics are on display in Aleppo. Even as ISIS forces in eastern Syria fight to evict the regime from its remaining outposts there, the government of President Bashar al-Assad in Damascus has concentrated on defeating the mainstream, non-jihadist opposition. Regime forces, backed by indiscriminate aerial bombardment, continue to encircle the rebels who control the eastern half of the city.
Meanwhile, just 15 miles to the north, ISIS is fighting the same poorly organized and underequipped rebel factions. ISIS’ strategic objective is to capture valuable ground that can serve as a gateway to the heart of rebel-held territory in the country’s northwest. The killing last week of several senior leaders in the rebel organization Ahrar al-Sham, a key adversary of ISIS, may ease its path.
Given Aleppo’s strategic and symbolic importance as a rebel stronghold, the very viability of mainstream anti-Assad forces in northern Syria is at stake in this battle on two fronts. The vital significance of this is that it is they who must take the lead on the ground in rolling back ISIS gains in Syria.
Among all who have fought ISIS since it emerged in 2003 (as Al Qaeda in Iraq), local Sunni insurgents have the most promising record. It was Sunni fighters who routed the organization in Iraq during 2007 and 2008, and in northwestern Syria early this year. Other forces on hand — what remains of the Syrian and Iraqi Armies, and the pro-Assad, Shiite and Kurdish militias — lack the necessary credibility with local populations to take and hold ground within ISIS’ main areas of control.
Without effective support, the opposition in Aleppo faces defeat. There are two ways of preventing that.
The first would be through a local cease-fire between regime and rebel forces in Aleppo. Regime forces would have to agree to withdraw from recently captured areas where they pose an immediate threat to the rebels’ one remaining supply line into the city. A deal like this would enable the rebels to shift resources to the fight against ISIS.
A local cease-fire would require a fundamental shift in the Assad regime’s strategy: Instead of prioritizing the defeat of the mainstream opposition, it would have to train its fire exclusively on ISIS. That is highly unlikely. The best hope for such dramatic change can come only through pressure from Iran and Russia, if they wish their Syrian ally to be part of the solution to the ISIS problem rather than one of its causes.
Failing that, the only alternative is for the mainstream opposition’s backers (including, but not limited to, the United States) to rapidly increase and improve their support to the rebels in greater Aleppo. That would entail funding, ammunition and anti-tank weapons, as well as improvements in cooperation among the backers themselves. Besides greater American investment in the process, Saudi Arabia, Qatar and Turkey must make coordination a higher priority than their respective relations with rebel groups.
The international partners must also work together to create incentives for pragmatic behavior and political engagement among rebel factions, while punishing indiscriminate tactics, sectarian rhetoric and criminal actions. One useful effect could be to strengthen the position of nonideological groups within the rebel balance of power.
The risks of boosting support to rebels are well known. Arms supplies might leak to Al Nusra Front, a jihadist group that has proved important to mainstream rebels as a tactical ally against the Assad regime and ISIS forces. Worse, matériel might even end up in ISIS’ hands, should its gains continue. Barring a significant de-escalation in the regime’s war against anti-ISIS rebels, however, there is no palatable alternative — airstrikes alone will not stop ISIS in Syria.
If mainstream opposition is defeated in Aleppo, ISIS will expand westward. And by appearing to be the sole Sunni force capable of sustaining war against the regime, ISIS will win still more recruits. There may be no second chances: As America is finding in Iraq, credible Sunni partners in the fight against the jihadis, once lost, are not easily replaced.
Jean-Marie Guéhenno, a former deputy joint special envoy for the United Nations and the Arab League to Syria, is the president, and Noah Bonsey is the senior Syria analyst, of the International Crisis Group.