President Barack Obama’s strategy to “degrade and ultimately destroy” the Islamic State in Iraq and the Levant (ISIL) relies entirely on allied forces on the ground doing the work that can’t be done by U.S. airpower. That formula may have made some progress in Iraq in recent weeks, but in Syria it lacks ready partners on the ground.

ISIL currently controls approximately 35 percent of Syrian territory, according to opposition-aligned human rights monitors, and fights against both the regime of Syrian President Bashar al-Assad and Syrian rebel forces. The question facing U.S. military planners is which forces on the ground will move in to clear and hold towns after ISIL positions have been bombed into retreat. Without such a partner, the U.S. will simply be repeating the Israeli approach to Gaza, cynically dubbed mowing the lawn by Israeli officials — an approach that not only fails to eliminate adversaries but can even work to their political advantage.

Obama has ruled out cooperating with Assad, whose forces control a bit less than half of Syria’s land mass (although a lot more than half the population lives in areas under government control). Instead, Obama informed the world that he would work with Syria’s “opposition.” Tellingly, he named no names.

The Syrian opposition remains notoriously fragmented and undependable. Obama did not name a militia or organization with which to partner because even after three and a half years of vetting rebel groups, the U.S. has yet to identify a credible ally.

U.S. intelligence estimates that Syrian rebels are organized into more than 1,500 groups of widely varying political leanings. They control a little less than 20 percent of Syrian territory. Those designated as moderate rebel forces control less than 5 percent of Syria. To arm and fund them without first unifying them under a single military and political command would be to condemn Syria to rebel chaos.

The U.S. is arming and funding 12 to 14 militias in northern Syria and 60 more groups in the south, according to the head of the Syrian Opposition Coalition. These militias have not, thus far, been particularly successful on the battlefield, and none has national reach. Most are based on one charismatic commander or a single region and have not articulated clear ideologies. All depend on foreign money.

The vast majority of Syria’s rebel groups have been deemed too Islamist, too sectarian and too anti-democratic by the U.S. — and these are the groups ranged against the ISIL. They span the Salafist ideological gamut, from al-Qaeda’s Nusra Front to the 40,000-strong conglomeration of rebel forces united under the banner of the Islamic Front. Despite U.S. skepticism, some of the Sunni Arab regimes Obama has courted as key allies in the anti-ISIL effort have worked with these groups.

Gulf countries reportedly poured money into the Islamic Front until the U.S. convinced them to stop. Islamic Front leaders decried democracy as the “dictatorship of the strong” and called for building an Islamic state. Zahran Alloush, the military chief of the Islamic Front spooked Americans by insisting that Syria be “cleansed of Shias and Alawites.” The newly appointed head of Ahrar al-Sham and the political chief of the Islamic Front earned his stripes in the ranks of the Iraqi insurgency fighting the U.S.

Turkey insists that the U.S. arm these anti-ISIL Islamist rebel groups, including the Nusra Front. Disagreement over which rebels to back is one of the reasons Ankara has refused the U.S. requests to use Turkish territory to train rebel forces and as a base from which to carry out attacks on ISIL. The United States’ principal allies simply do not agree on which rebel forces are sufficiently moderate to qualify for support.

Last year the U.S. tried to unite Western-friendly militias under a supreme military command, but that effort proved a debacle. In December the Islamic Front overran the supreme military command of the Free Syrian Army and ransacked its numerous warehouses and depots, making off with large stashes of U.S. and Saudi supplies. The U.S.-backed fighters were hogtied and left in their underwear. When U.S. Ambassador Robert Ford requested that the Islamic Front return the stolen items, he received no response.

No less that three commanders profess to be the rightful supreme military leader of the Western-backed Free Syrian Army — and all decry Obama for having betrayed them. He has not exactly heaped praise on the group either, claiming it was a “fantasy” that the group of “doctors, farmers, pharmacists and so forth” could overthrow Assad.

Obama has been in no hurry to arm the rebels or bet on them. The half-billion dollars he has requested for their training is chump change if it’s intended to create a force capable of taking on Assad’s military. The U.S. spent hundreds of billions to build the Iraqi army, which nonetheless crumbled in the face of ISIL.

Beyond the competence and orientation of rebel groups, there’s substantial division between the U.S. and its allies on the question of goals in Syria. Obama has made clear he envisages supporting the rebels only insofar as they fight the ISIL and secure areas from which it has been driven; he will not support their war to overthrow Assad. Despite insisting that Assad has no legitimacy and must step aside, Obama supports a political solution in Syria. That position makes sense for U.S. interests but not to Syrian rebels.

Washington wants to contain Syria’s violence in Syria. If rebel forces overran the key cities that remain under regime control — Damascus, Hama, Latakia, Jable, Banyas, Tartus and Suwayda — a second tsunami of refugees would pour out of Syria, threatening the stability of neighbors.

And with the regime having been built around Alawite supremacy and the armed rebellion being overwhelmingly composed of Sunnis, the civil war is being fought on sectarian lines, and prospects for a political solution short of partition remain remote.

While Obama’s speech may have raised hopes among rebels and their foreign backers that the U.S. will finally intervene to tip the balance in Syria, his goal remains far more limited: an air campaign to degrade ISIL capabilities. Even that intervention is rejected by Damascus and its foreign allies, and its narrow limits are likely to frustrate the rebellion and the U.S. allies seeking more robust backing for the armed overthrow of Assad.

Fixing the deep-seated political breakdown of which ISIL’s rise is one symptom is beyond Obama’s capability. Ten years of nation-building by more than 100,000 U.S. troops in Iraq failed to create a new stability, and today’s challenge of failing statehood extends way beyond Iraq. Bombing is envisaged as a Band-Aid solution to the region’s problems. But the wounds run deep and wide.

Joshua Landis is the director of the Center for Middle East Studies at the University of Oklahoma.