Once again, a Kurdish ally of the United States has no idea where it stands with Washington. Since 2014, the Kurdish People‌s Protection Units (YPG) has received arms and military advice from the United States, and proved instrumental in the campaign against the Islamic State in Syria and Iraq. But with the Trump administration signaling its intention to pull U.S. troops out of Syria, the YPG suddenly faces an uncertain future. Hedging its bets, the YPG has twice sent a delegation to Damascus over the past month to start negotiations over a possible transition in northeast Syria. But the regime, on the verge of victory in Syria‌s seven-year civil war, has proven inflexible.

Bashar al-Assad, the president of Syria, has repeatedly announced his intention to reclaim “every inch” of Syrian territory. That includes the zone controlled by the YPG, an area that also comprises the majority-Kurdish region the Kurds call Rojava. The question is how and when he will attempt to do so. The answer depends, in part, on what role Russia and the United States will play in managing the future of northeast Syria; both have a stake in the outcome, and could conceivably find common ground on the Kurdish question.

Syrian Kurds are discovering that their vital role in the fight against isis may not have secured Washington‌s help in their struggle against their other enemies. As a stateless people sandwiched between Syria and Turkey, two countries bent on keeping them down, they must rely on external backers such as the United States to give them a margin of freedom and autonomy. But the United States is a fickle friend indeed.

Last year, Iraqi Kurds had a foretaste of what can happen when you misread or ignore Washington‌s strategic interests. Iraq‌s Kurdish region held an independence referendum, hoping to gain leverage in negotiations with Baghdad about an eventual separation. The Trump administration warned them not to proceed, citing poor timing, as the fight against isis was still ongoing. The administration then did nothing when Baghdad imposed heavy sanctions on the region and forcibly took disputed territories back from Kurdish control. The Iraqi Kurdish leaders learned that a global power won‌t rush to their aid if they threaten its interests: in this case, protecting the fight against isis and preserving a unified Iraq as a bulwark against Iranian influence.

Today, the YPG faces a similar predicament. It is a Syrian affiliate of the Kurdistan Workers‌ Party (PKK), which has fought an insurgency against the Turkish state since the 1980s; Turkey, the United States, and the European Union have designated the PKK a terrorist organization. Despite the YPG‌s shared genealogy with the PKK, Washington supported the group because of its battlefield prowess. As it beat back isis, the YPG took control of additional non-Kurdish territory in Syria, including the mostly Arab cities of Manbij and Raqqa.

But with the Assad regime resurgent, all those gains could be reversed. Aided by control of the skies over much of Syria and its veto power in the United Nations Security Council, as well as ground forces supplied by Iran and its allied militias, Assad‌s forces have taken back rebel-held territory over the past two years. They hope to finish the job in the coming months, and are primed to move on Idlib, the final rebel holdout. Soon after that, the regime will tell the YPG to give up the area it surrendered to the group in 2012. (It did so in order to free its own forces to fight off the popular uprising further south.) Assad needs the YPG-held region‌s vast wheat fields and oil fields—Syria‌s largest—to rebuild.

Turkey, too, has an important stake: It does not want the YPG, and by extension the PKK, running a Kurdish enclave in Syria directly on its border. In February, Turkish forces invaded the Kurdish district of Afrin in northwest Syria, wresting it from the YPG as Russia and the United States stood by. The group now fears that the story will play out again in Syria‌s northeast, not in the least because Turkey has said it wants to drive them out.

This is why the YPG has looked to Assad for a way out. A compromise on a postwar arrangement for the Kurdish region might be possible. Such a deal could include a certain degree of Kurdish autonomy and the sharing of oil wealth. Yet there‌s still considerable daylight between the YPG and the Assad regime. While Damascus may prove flexible on matters concerning Kurdish culture and language, it rejects the full autonomy sought by the YPG—especially where its security forces are concerned. YPG leaders have told the International Crisis Group that they would consider handing over civil administration of the areas they govern to Assad, and could even be convinced to formally integrate their fighters into the regime‌s security architecture. But they would insist that the YPG police the Kurdish-majority areas. The Assad regime does not appear to be in a hurry to reach a solution: It has time (and Russia and Iran) on its side.

This is where the Trump administration could play an important role, should it choose to. It still has some 2,000 military personnel on the ground in northeast Syria, a legacy of the not-yet-finished fight against isis. While President Donald Trump said in March that he wants all U.S. troops out of Syria, his senior foreign-policy advisers view a continued U.S. military presence as both a potential block to perceived Iranian expansionism and as leverage to shape a political transition in Damascus. A precipitous, unconditional U.S. withdrawal would set the stage for escalating conflict among competing forces in Syria‌s northeast. It could even leave the terrain open for isis to resurface.  

Things need not go this way. The United States could use its presence to provide its Kurdish allies with time, space, and security to reach an arrangement with Damascus on key questions of control and governance—one that is also acceptable to Ankara. For the YPG, this would be the best possible outcome under the current circumstances.