Syria’s northwest, centered on Idlib province, is the final redoubt of the country’s insurgents in their fight against the regime of Bashar al-Assad — their last castle.

That fight — between the Idlib-centric insurgency and the Assad regime — is not America’s fight, nor is it the fight of its Western allies.

Some have recently argued the United States and its allies should backstop Idlib’s rebels more or less indefinitely, both to defend civilians from the Assad regime and to maintain some non-extremist alternative. These proposals are untenable — unmoored from strategic logic and disconnected from the reality of Idlib’s rebellion, which is by now dominated by jihadists. The West should not sustain a jihadist-led section of the Syrian rebellion in perpetuity, to no obvious end and against a backdrop of ongoing, senseless civilian death. Instead, America and its Western allies ought to be ensuring that, when armed conflagration engulfs the northwest, civilians can get to safety.

Greater Idlib is Syria’s lone rebel stronghold that hasn’t been besieged or turned into a proxy-manned buffer zone by one of Syria’s neighbors. It represents the rebellion’s last real challenge to the regime, both because of its ready supply lines into Turkey and because it is dominated by jihadist and Islamist rebel factions that can’t be properly controlled by foreign backers. First among them is Hayat Tahrir al-Sham (or just “Tahrir al-Sham”), the super-sized successor to Syrian al-Qaeda affiliate Jabhat al-Nusrah.

The northwest is also jammed with vulnerable civilians. According to my own estimate based on the International Organization for Migration’s Needs and Population Monitoring data for March 2017, the rebel northwest — including Idlib and adjacent sections of Aleppo, Hama and Latakia provinces — holds in excess of 2.3 million people. That includes more than 900,000 internally displaced persons (IDPs) who have fled the regime’s bombing and its creeping advance on the ground and now shelter in rented apartments or camps clustered along the Turkish border. Conditions for these people, especially the displaced, are bleak. Hundreds of thousands survive on relief aid such as food baskets and blankets. It’s a sort of half-life, as new generations of Syrians grow up with minimal education, little experience living under a state or the law, and few apparent prospects.

On a recent trip to Turkey, humanitarians told me the sheer need is overwhelming. Abdulqader al-Asmar, an officer with Syrian relief NGO Binafsaj, explained:

After every airstrike, you have needs, of all sorts, that are created anew. People lose their homes, people have new medical needs, people are starting over at zero, people are injured, stores and markets are damaged.

“This is really much worse than a disaster,” said Mehmet Güllüoglu, Director-General of the Turkish Red Crescent, who spoke to me in his Ankara office:

In disasters, the effects and the results decrease slowly. But in this kind of — really, this is a complex humanitarian emergency — every day it gets difficult. That’s why, even for emergency relief operations, sometimes we cannot fulfill the needs.

Many IDPs are apolitical or lukewarm about the revolution, Syrian rebels and activists have told me, but they’ve fled to opposition areas because they fear the regime will detain and torture a loved one, or forcibly conscript a male family member into the Syrian military. And lately, the Assad regime has used Idlib as a dumping ground for undesirables bussed out of “reconciled” towns in the Homs and Damascus countryside.

“The support is never enough,” said Muhammad Jaffa, now the chief coordinator for the effort to accommodate civilians deported from Homs and Damascus.

In an Antakya café, Jaffa told me about receiving busloads of people in the Hama town of al-Madiq, the crossing point from regime territory into the rebel northwest. Locals have run out of places to host them. In the meantime, they’ve divvied up the new arrivals between mosques and their own homes. He sometimes collapses into tears when he thinks about children he’s seen arrive in Hama after going hungry in besieged towns, he told me. They stuff themselves with food, he said, only to vomit it back up.

The regime seems to have deliberately turned Idlib into a shooting gallery full of irreconcilables, just as, since the start of Syria’s revolution in 2011, it has molded the insurgency into something too extreme for most would-be foreign backers.

In the northwest specifically, the mix of jihadist and Islamist factions makes most foreign support — certainly Western support — for the armed opposition basically unsustainable. Tahrir al-Sham has by now firmly dug itself into the northwest. It has ostensibly broken with al-Qaeda and claims it has no ambitions to launch attacks abroad, but it remains tied into global jihadist networks and it continues to turn out experienced, technically capable jihadist cadres that might wreak havoc across the world. The United States and its allies provide salaries, rations, small arms and ammunition, and anti-tank weapons to non-jihadist rebels in the northwest, both traditional “Free Syrian Army” nationalists and soft Islamists. But a not-inconsiderable amount of that support is skimmed by Tahrir al-Sham. Further, rebels regularly coordinate with Tahrir al-Sham and play an auxiliary role in jihadist-led operations. For rebel groups whose raison d’être is fighting Assad and who do not want to be destroyed by jihadists, this makes sense. For Washington, it does not. Continued support for the northwest insurgency amounts to effectively subsidizing a jihadist safe haven in the Levant.

Threatening the regime with a section of Syria’s insurgency spearheaded by al-Qaeda-style jihadists will not somehow convince the regime to negotiate a compromise. And Idlib’s rebellion is distinct from smaller enclaves in east Aleppo or north of the Jordanian border, areas whose rebels are more attractive to the West but, for various reasons, incapable of making a run at Damascus. As monstrous as the Assad regime is, the West does not and should not want to see Idlib’s rebels overrun the regime and win the country.

Tahrir al-Sham’s dominance can’t be undone in Idlib. Western-backed “Free Syrian Army” rebels can’t and won’t challenge the group. The best hope for rebalancing the northwest seems to be Ahrar al-Sham, an Islamist movement and rival opposition faction. But Ahrar al-Sham is itself a problematic partner for the West. And while Ahrar can stop specific Tahrir al-Sham aggressions when it tries to muscle local rebels into surrendering their weapons stocks, Ahrar refuses to start an open war against its hardline counterpart. If it tried, it likely couldn’t motivate many of its fighters to participate.

If Tahrir al-Sham can’t be defeated from inside Idlib, maybe it could be defeated from without. Turkey in particular seems best positioned to intervene and dislodge Tahrir al-Sham. Yet I was told recently by Turkish officials and experts, Western diplomats, and Syrian rebels that Turkey has other priorities. As one Western diplomat in Turkey told me, “I think we’re going to wear the problem of Jabhat al-Nusrah much longer than the problem of Daesh [the Islamic State].”

The Syrian regime seems uninclined to cede any part of territory to the Syrian opposition. But with the rebel northwest in particular, there can be no peace. There will be no negotiated devolution of political authority or autonomy for a home base for incorrigible, jihadist insurgents. Even a ceasefire is unworkable, given the critical mass of jihadist spoilers and the regime’s own intransigence.

In the northwest, a terrible showdown is likely coming. The regime is already pummeling it from the air. It was in southern Idlib that the regime allegedly deployed chemical weapons on April 4. Since then, the regime and its allies have used conventional weaponry to devastating effect and reversed what gains rebels had recently managed.

For rebels, the northwest may be their defiant last stand. But for millions of civilians, it’s a cage.

Turkey has shut the official Bab al-Hawa border crossing into Idlib to most civilian traffic, and it has substantially tightened security along the border between Idlib and Turkey’s Hatay province. Not everyone wants to leave the northwest, but many do. People now pay between $400 and $2,000 to be smuggled across, but more can’t afford it and are stuck in a war zone.

It was the people left behind who kept Syrian relief workers like him motivated, Abdulqader al-Asmar told me in Binafsaj’s Antakya office. He and his colleagues had themselves been hungry, gone without water, and been displaced over and over. “We got an opportunity, maybe because we were able to settle somewhere stable, and we could help our community,” he said. “Imagine how many people there are inside Syria that are looking for that sort of opportunity and can’t find it.”

U.S. and allied policy in northwest Syria, as it is currently oriented, is meant to keep civilians in place inside the country. That includes all major lines of policy effort. Relief covers people’s basic subsistence needs, stabilization assistance creates a semblance of governance and service normalcy, and military support for rebels keeps the regime’s forces at bay. The latter two species of support also have a dubious counterextremism logic, as foreign backers work to prop up moderate alternatives to jihadists. All of this is intended to put a positive, hopeful sheen on a circumstance that is unlivable and unsafe, and which people should leave.

There is no clear endgame to this policy. At some indeterminate point — after undefined intermediate steps — the idea is that foreign support will have produced conditions conducive to the deradicalization of Idlib and a negotiated settlement that reintegrates the northwest in a whole Syria.

These things will not happen. The longer the opposition’s backers fiddle with a plan to rebalance Idlib’s armed opposition and marginalize the jihadists — a plan that, to be clear, will fail — or hold out for a political solution that is not coming, the longer the northwest’s civilians live in lawless dysfunction and deprivation, and the more of them die.

How long is this supposed to last? And for what?

I am not arguing that the United States and its allies should force the displacement of the northwest’s residents, which would amount to a war crime. But if a cataclysm is coming — and I’m convinced one is — the West needs to ensure these civilians are able to flee to safety.

I asked Muhammad Jaffa what would happen if the regime and its allies trained their fire on Idlib. He pointed inside his coffee cup. “People are in the center of this cup,” he said. “Where are they supposed to go?”

“Idlib is like al-Wa’er,” he said, referring to a Homs city neighborhood whose residents were besieged for years. “It’s just bigger, that’s all.”

Not everyone inside Idlib will run towards Hatay. Some civilians can probably flee safely to areas of regime control, and others into the Kurdish enclave of Afrin north of Idlib. And some civilians will hold out in the northwest until the end, bound either to their ancestral homes or, by familial ties, to local rebels.

But many will try to escape to Turkey. Ideally, the West can convince the Turkish government to allow these civilians across. But Turkey is already straining to accommodate nearly 3 million Syrian refugees, which is why it has lately tried to push for “safe zones” inside Syria, and Turkey is itself politically unsettled. It can’t be taken for granted that Turkey will let new refugees in. The West has to make sure there isn’t a mass-scale repeat of the northern Aleppo border in May 2016, when the Islamic State closed in on an estimated 100,000 people and Turkey refused to allow them to cross.

I asked the Turkish Red Crescent’s Mehmet Güllüoglu if he thought, in a worst-case scenario, that Turkey would open its border to a refugee exodus. “I have no idea,” he said. “Three million is a big number. Three million plus one million is another big number.”

The Turkish state will have its own reasons for allowing Syrians to enter, or not. Domestic factors ranging from many Turks’ resistance to new Syrian migration, to Turkish president Recep Tayyip Erdoğan’s personal investment in the Syrian conflict and his desire to position himself as a beneficent Muslim leader, will be central to Turkish decision-making. But the United States and its allies should try to put their thumb on the scale without rankling the Turks by seeming to lecture or dictate to them. Turkey has been unhappy about the international community’s insufficient contribution to its expensive accommodation of millions of Syrian refugees. The West should offer to further subsidize Turkey’s refugee burden, but it should also make clear that Turkey’s recent crackdown on international relief NGOs is counterproductive. European allies may also be able to provide expert assistance on refugee integration, with which Turkey has little real experience and on which Turkey currently has no strategic direction. And for the United States and others, this refugee issue is only one equity among many in their respective bilateral relationships with Turkey, which also encompass linked issues ranging from economic ties to the NATO alliance relationship to support for Kurdish forces in Syria. If Turkey wants to trade refugee access for other, seemingly unrelated policy priorities, the United States should look for a deal that’s viable.

If Turkey still proves unwilling, then the United States should coordinate with Kurdish forces in the Afrin pocket north of Idlib. Afrin already hosts Arab IDPs, and local forces allow some civilians to transit between rebel-held territories on either side through Afrin. Kurdish units may be willing to allow the safe movement of larger numbers of civilians into Afrin or beyond to the eastern Aleppo countryside, which is an effective safe zone under Turkish control. The United States can offer inducements to Afrin’s Kurdish forces, including further gestures of political recognition, or expanded military support in Syria’s northeast. America has limited direct ties to Afrin forces, but it can deal with related Kurdish forces in the northeast or involve Russia as an intermediary to deal with Afrin.

I’ve been told by Western diplomats that there is some advance planning underway. But the test will come when things get chaotic and scary, and people either cross to safety or get bombed to death or shot trying to approach a border wall.

The proxy war against the Syrian regime in the northwest, for the West, is lost. The United States should be working to scale back its involvement in Syria’s war and, where possible, de-escalate the conflict and freeze current lines of control. That is not possible in the northwest. The fight between this jihadist-dominated fragment of the Syrian insurgency and the Assad regime will rage on. And in that fight, the United States and its allies have no clear rooting interest, no side to boost.

America and its allies should be on the side of the civilians caught in the middle. They need help.

Sam Heller is a fellow at The Century Foundation and a Beirut-based writer and analyst focused on Syria. Follow Sam on Twitter: @AbuJamajem.