It didn’t have to be this way. The U.S. worked endlessly to placate our Turkish allies.

We engaged in countless rounds of negotiations, committing to establishing a security mechanism that included joint patrols in areas of concern to the Turks, and deploying 150 additional U.S. troops to help monitor and enforce the “safe zone.” Yet Ankara repeatedly reneged on its agreements with the U.S., deeming them inadequate and threatening to invade SDF-held areas, despite the presence of U.S. soldiers.

A possible invasion from Turkey against the Kurdish elements of the SDF, coupled with a hasty U.S. departure, now threaten to rapidly destabilize an already fragile security situation in Syria’s northeast, where ISIS’s physical caliphate was only recently defeated. Nearly 2,000 foreign fighters, about 9,000 Iraqi and Syrian fighters, and tens of thousands of ISIS family members are being held in detention facilities and displaced-persons camps in areas under SDF control. What happens if we leave? The SDF has already stated that it will have to fortify defense mechanisms along the Syrian-Turkish border, leaving ISIS detention facilities and encampments with little to no security. This is particularly troubling given the self-proclaimed caliph of ISIS Abu Bakr al-Baghdadi’s recent sermon called on supporters to break fighters out of these facilities, and amid violent attacks in the al-Hol refugee camp, where tens of thousands of women and children are housed and where ISIS sympathy runs rampant.