The Syrian civil war, which has dragged on for three years, has until now been deadlocked in a bloody war of attrition. However, the forceful emergence of ISIS, renamed the Islamic State (IS), may ironically have opened the door for a change in the conflict.

IS, with its rash of victories in both Iraq and Syria, is forcing all belligerents, neighboring countries, and interested powers to rethink their approaches to the conflict. Once upon a time, Syrian President Bashar al-Assad may have hoped for a jihadist organization to emerge as his principal foe, so that he could demonstrate to the world that he is by the far the most reasonable party to this conflict. But the organization that has emerged, IS, may turn out to be more than he bargained for.

IS’s sheer brutality and its routing of the Syrian army at the air base in Raqqa last month have the potential to trigger some fundamental changes. IS not only overpowered the Syrian army in Raqqa; it also, in a show of utter barbarity, marched some 170 hapless half-clad soldiers through the desert sand and executed them en masse. It then publicized the heart-wrenching photographic and video evidence of these deeds to further intimidate its opponents. The Syrian regime, which had pretended that it had implemented a well-organized retreat, now faces a terrible public relations debacle as well: How can it explain itself to the mothers and fathers of the executed soldiers?

It is ordinary Syrians, whether pro- or anti-Assad, who has been paying the awful costs of this war. The execution of these soldiers is likely to kindle new angst and questioning among Assad’s supporters. How many more such events are likely to take place? How long is this war going to last? The London-based Syrian Observatory for Human Rights estimates that the death toll for the Syrian Army, its affiliated militias, and the Iranian-trained National Defense Forces is 110,000. Considering that a large segment of Syrians no longer live under government control or are refugees in neighboring countries, the burden of further casualties is falling to a smaller and smaller portion of the population.

Until now, Assad had managed to convince his supporters that his regime was the only thing standing between calamity and survival. He may no longer be able to sell this proposition. If not, then his supporters may come to believe that their only choice is between calamity—that is to say, losing their children to an endless war—and Assad’s ouster.

Assad’s wish that an IS-like organization would galvanize support in forms like the limited airstrikes ordered by President Obama is not getting much traction. The U.S. has already indicated that it will not be baited into collaborating with Assad against IS. In fact, the right strategy is to double-down in Iraq, by helping the incoming government and the Iraqi Kurds to regain lost territory. Unlike in Syria, the U.S. in Iraq has local parties it can collaborate with.

By contrast, IS’s success and resilience to date are more likely to make members of Assad’s security services and supporters rethink their positions. Paradoxically IS may actually form the basis of a clear call for his removal; the possibility of an IS victory in Syria, however small, is far too awful to contemplate.

This new dynamic provides the Obama Administration with a unique opportunity to deliver a clear and unambiguous message to Syria: If Assad is removed (this has always been the single most important demand of the opposition), then Washington will work with anyone in Damascus who does not have Syrian civilian blood on his or her hands; with the Syrian army (but not the militias); and with the opposition, both political and armed, to make common cause against IS. The U.S. should then set out exactly what it is prepared to do. How will it support a new government in Damascus, which, in all likelihood, would be composed, of military officers? How will it help a process of reconciliation? How will it use its influence to mobilize an international effort (and specifically the Gulf Arabs) to rebuild Syria. The U.S. can invite leaders from all interested parties and governments to a summit where this is all laid out in concrete.

Having invested so much in Assad’s continued rule, will the Russians, Iranians, and Hezbollah stand in the way? Probably not in the Russian and Iranian cases, but Hezbollah may resist for a while. With the exception of the latter, which sacrificed fighters in the conflict at the request of Tehran, the others have supported Assad for their own strategic reasons. The brutality of IS has succeeded in bringing together many who were once at odds with each other over Syria, and it has opened a door to international collaboration. But most importantly, it has also cleared the way for the possibility of new thinking in Damascus. Even for Russia and Iran, therefore, it has become foolhardy in the long run to support Assad, and thereby become IS’s enablers.

This effort may still fail, but the time is ripe for some imaginative thinking on Syria at the White House. In coming up with a new alliance, the White House may be thinking that it is advancing the fight against IS. However, what it really needs to do is make a careful assessment of the situation, followed by a strategy that exploits the weaknesses of both the Assad regime and IS. Form, one should always remember, follows function.