A month ago the Syrian Arab Army (SAA) took control of the Castillo Highway in northern Aleppo, the rebels’ last supply route into their eastern redoubt. By July 27 it looked like the complete reconquest of Syria’s largest city by government forces was only a matter of time. In the first week of August, however, the recently rebranded Jabhat Fatah al-Sham (aka al-Nusra Front) staged a surprise counterattack at Ramouseh, southwest of the city center, and threatened the government’s own key supply route into the city. Fierce and often confusing back-and-forth fighting has continued ever since, with both sides laying siege in some areas while at the same time being under siege in others.

For the past three years Bashar al-Assad’s strategy has been based on reestablishing control over Syria’s most populous and economically viable third, from the Mediterranean coast and Aleppo in the north to Damascus in the south, with Homs in the middle. The main problem the SAA faces is limited manpower. After more than five years of battlefield attrition, the pool of reliable Alawite recruits—the backbone of the army’s front line units—is drying up. Government forces have displayed considerable resilience, and Russian air support would not have changed the balance of forces on the ground if the SAA was not an effective fighting force. Nevertheless, this summer’s fighting in and around Aleppo may have marked the limit of the army’s current offensive capacity in labor-intensive operations. That capacity may be bolstered, but only to a limited extent, if Iran steps up training, arming, and stand-off capabilities of local and foreign Shia militias which have been acting as the SAA’s auxiliaries.

In the longer term, various Salafist outfits—the only fighting opposition in Syria—will be in serious trouble if President Recep Tayyip Erdogan softens his resolutely anti-Assad position, which is a distinct possibility in the light of his recent rapprochement with Russia and the post-coup chill in his relations with Washington. Having visited Putin in St. Petersburg on August 9, Erdogan is going to Tehran next week hoping to improve relations. Turkish Prime Minister Binali Yildirim has already said that it is time for Ankara to normalize ties with Damascus and resolve the Syrian crisis “in cooperation with other regional players.”

If Erdogan makes a u-turn on Syria, the jihadists’ supporters and sponsors in Saudi Arabia and the Gulf will try to keep demands for U.S. intervention against Assad alive with a constant stream of atrocity-management stories. They expect that Hillary Clinton’s victory would promptly redirect U.S. policy towards no-fly-zones, air strikes, and regime change. They are therefore desperate for their protégés to cling on to at least some parts of Aleppo, both for its propaganda value (“World inaction turned Aleppo into Stalingrad”) and as a strategic hub that could become the focal point of the hoped-for U.S. intervention in early 2017.

That intervention would be a disaster for America and the region. No “moderate opposition” exists in Syria. The regime’s downfall would be followed by massive carnage, by new waves of refugees heading west, and by the imposition of a jihadist dictatorship. Whether it would be controlled by al-Nusra (under whatever name) or by ISIS itself would be irrelevant to the millions of Syria’s beleaguered Alawites, Christians, Druze, as well as many moderate Sunnis who do not cherish the prospect of living under sharia.

Syria will never be a stable democracy ruled by a moderate, pro-Western government. As such she is no exception to the rest of the Arab world. It is in the American interest to prevent the emergence of a Syrian caliphate that would further destabilize the region and send fresh millions of refugees to Europe. It is unfortunately too much to expect that geopolitical prudence and strategic balancing of ends and means will prevail if Hillary Clinton returns to the White House next January.