Land was once the biggest asset of the so-called Islamic State, giving the group its core claim to legitimacy. Today, in the immediate aftermath of losing its last pocket of territory in eastern Syria, women are its most prized asset, giving the group perhaps its last chance of survival.

This is quite a turnaround for one of the world’s most violently misogynist organizations, which commoditized women, bought and sold sex slaves, and trafficked in teenage girls.

With increasing pressure on Western governments to take back their citizens who left to join ISIS, understanding the role of committed ISIS women has never been more urgent.

Earlier this month, in al-Naba, ISIS’ weekly Arabic-language newsletter, an article implored ISIS fighters in Baghuz, which was then the last remaining sliver of the so-called caliphate, to remain steadfast in the face of the ongoing military onslaught by the Western-backed SDF (Syrian Democratic Forces).

Commenting on the article, the BBC’s jihadist specialist Mina Al-Lami said that ISIS “is clearly desperate for its members to fight on and not surrender, reminding them of the rewards of dying as ‘martyrs’ and warning them of the grim consequences in this life and ‘the next’ if they opted for surrender.”

What ISIS didn’t call for was the immediate military enlistment of the remaining women in Baghuz to join their husbands on the battlefield in a last ditch, gender-equal, armed resistance against the encroaching SDF.

This is notable, since in earlier pronouncements ISIS had made it clear that women could fight if their survival depended on it. But the call never came, and it is important to understand why. ISIS’ decision to keep women out of the fight now sheds a sharp light on the way it plans to regenerate over the next few years of what it sees as inevitable trial and tribulation.

Jihadist groups are deeply patriarchal structures in which women, by and large, are prevented from playing military roles. Indeed, the norm on which they are founded is that men have the monopoly over the use of violence. Jihadi women, by contrast, have the monopoly over the household and family; in most jihadi groups women are first and foremost wives and mothers.

In ISIS a small group of women were given more leeway, branching out as online propagandists, where they encouraged other women to join the group. A few were members of the hisba police, shaming their more lax sisters to pipe down and cover up. Some participated in the trafficking of other women from Yazidi sex slaves to Western hostages like Kayla Mueller. But most were glorified chattel.

The jihadi prohibition against women’s participation in combat isn’t set in stone. It can be suspended if the very existence of the jihadist group is on the line—when, that is, the “heavens are about to fall.”

There can be little question that earlier in the year the heavens were about to fall for ISIS as a territorial-based entity. Yet it never invoked the emergency measure of sending out waves of its female members into combat against the SDF. In fact, the opposite occurred: ISIS sent out droves of women and children to surrender to the SDF.

This is especially curious because it went against some of the noises ISIS had made previously about women and jihad. In October 2017 an article in al-Naba declared that “it has become necessary for female Muslims to fulfil their duties on all fronts in supporting the mujahideen in this battle,” adding that women should “prepare themselves to defend their religion by sacrificing themselves by Allah.” In early 2018 ISIS released a video that showed a veiled-up figure wielding an AK-47 in battle.

These references to women and jihad were not clear-cut, in that they didn’t explicitly command women to join their male counterparts as armed combatants on the front line. But they certainly hinted at this possibility.

On the ground, however, it never happened: women were not dispatched to the front in significant numbers. Some reportedly launched suicide operations in Mosul in 2017, but most stayed at home, where they were killed or captured, and while grainy footage has recently surfaced of what appeared to be women in combat in Baghuz this spoke more of frenzied desperation than of any meaningful strategic shift on the part of ISIS.

Experts are now warning that female members of ISIS are a serious security risk, especially those seeking to return to their countries of origin. “Many,” cautioned the head of the U.K.’s Metropolitan Police counterterrorism command, Richard Walton, “will pose just as much of a security threat as their male counterparts.”

But the idea they will fight or carry out terror attacks just the way men do is misplaced. The threat they pose may be more long-term and in its way more sinister.

Thomas Hegghammer, a scholar of jihad, notes that educated Westerners, imposing their own egalitarian norms, want to think jihadist women have agency and are the equal of men on the terrorist battlefield, thus leading to assumptions about ISIS women as ticking female bombs ready to detonate at any minute. But the chief risk that these women pose lies not in their activation as combatants, it’s as incubators of the next generation of ISIS fighters.

As a recent report by the Middle East Institute warned, “The seeds of ISIS 2.0 reside in the prison population being held in detention by coalition partners in areas liberated from ISIS,” and much of that population consists of unrepentant ISIS women and their children.

Over the past few weeks thousands of ISIS women and their children have surrendered to the SDF. And it appears they have done so with the blessing of ISIS’s remaining leadership.

In a recent France 24 documentary on ISIS foreign women in the Kurdish-controlled Al-Hawl camp in north-eastern Syria, a camp director said that “when they [foreign ISIS women] gave themselves up, some of them told us that the IS group briefed them, telling them, ‘Surrender, go back to your countries, get your strength back and we will start again.’”

Referring to other ISIS foreign women who had expressed regret, he said, “The problem is their intentions; they tell us what we want to hear, but we have no idea about what they really think.”

Other reports have described how senior-ranked ISIS women have defiantly sought to recreate the caliphate’s totalitarian norms inside the camps where they are being detained. Referring to the children of these women, Nadim Houry, the director of Human Rights Watch’s terrorism and counterterrorism program, warned that “radicalization is going to continue to be a problem.”

“We left so that Allah can give us another generation to become mujahideen,” a captured ISIS woman recently told a journalist in Syria. “With the will of Allah, we will bring up this generation—the youngest to the oldest.”

It was a stark and sobering warning, and one the international coalition against ISIS must pay close attention to. The fighting in Baghuz is now over. But the battle for hearts and minds rages on. And it is here that ISIS women are leading from the front.