More than three years after it thundered out of the Syrian-Iraqi desert on its genocidal rampage and spread its tentacles from northern Africa to central Asia, the so-called Islamic State has suffered its worst week ever. Newly emboldened Iraqi army and militia forces ejected ISIS from its second-largest urban stronghold in Mosul, while Kurdish YPG forces began seizing ground in its so-called capital of Raqqa. Russia and the US signed off on a cease-fire in southwestern Syria which will allow the US and its allies a freer hand to operate in the east against ISIS forces.

As its forces reel backward from a sustained assault, their leadership has taken even more serious blows. The latest of these took place in Afghanistan, where the US claimed success in killing ISIS-K leader Abu Sayed in a drone strike. This comes during an intense focus on shutting down the ISIS franchise, and Sayed didn’t shuffle off the mortal coil alone:

Other members of the group were also killed in the operation, the Pentagon said in a statement, which asserted that the attack would “significantly disrupt the terror group’s plans to expand its presence in Afghanistan.” …

Mr. Sayed was chosen to lead the group in Afghanistan after his predecessor, Abdul Hasib, was killed in April during a special forces raid in Nangarhar Province, where the militant group has been active. Two United States Army Rangers were killed in the April operation, perhaps by so-called friendly fire, the Pentagon has said.

In Afghanistan, the group goes by the Islamic State in Khorasan, an ancient name for the region that includes portions of Afghanistan and Pakistan. It has sought to expand the scope of its operations in Afghanistan, but the location of the latest strike, in Kunar Province, suggests the group may be falling back from its stronghold of neighboring Nangarhar.

The NYT’s Michael Gordon notes correctly that ISIS, like the Taliban, usually replace leaders quickly after they get killed. This time might be more difficult, however, since the home office is presently struggling with the same problem. Several sources in Iraq and Syria reported that ISIS announced the death of the self-appointed “caliph,” Abu Bakr al-Baghdadi to the city of Tal Afar, which ISIS still controls, and warned of an emerging civil war within the organization. The US has still been unable to directly confirm Baghdadi’s demise, but neither has anyone heard from Baghdadi or any rebuttal from ISIS.

Iraqi’s Alsumeria News, which provided the first reports of the Tal Afar announcement, later picked up on an alleged power play within the group:

A senior Islamic State leader in Kirkuk’s Hawija has declared himself a new supreme leader, adding to the state of chaos within the group’s ranks that followed reports of the death of the group’s founder, Abu Bakr al-Baghdadi.

“Abu Haitham al-Obaidi, deputy to the (Islamic State’s) mayor of Hawija, dissented from the group and named himself a new Caliph after Baghdadi’s death reports were confirmed,” said Jabbar al-Maamouri, a leader at the Popular Mobilization Forces, in statements to Alsumaria News.

This seems suspect, at least in terms of being taken seriously. Reuters noted the possibility of Iyad al-Obaidi of Hawija making a bid to take over the group, but noted that al-Obaidi would lack the fundamental requirements of a caliph — a clerical background and a physical state to rule:

Baghdadi awarded himself the title of caliph – the chief Muslim civil and religious ruler, regarded as the successor of the Prophet Mohammad – in 2014. Obaidi or Jumaili would be unlikely to become caliph because they lack religious standing and Islamic State has lost much of its territory.

“They don’t belong to the Prophet Mohammad’s lineage. The group has no longer ‘a land to rule’ or ‘Ardh al-Tamkeen’. And none is well versed in Islamic theology,” said Fadhel Abu Ragheef, another Iraqi expert on the extremist group.

“A caliph has to have an Ardh al-Tamkeen, which he rules in accordance with Islamic law. Failing that, the successor will just be recognized as the emir,” said Hashimi.

It’s much more likely that the succession will get determined by bloody infighting between would-be warlords, and that none of them will credibly claim the title of “caliph” even within the terrorist army. That internecine war will make it much more difficult for ISIS leadership to coordinate with its satellites in Afghanistan, Libya, and elsewhere in the region. Local warlords looking for their own opportunities will have a chance to seize power, and that will reduce their own credibility and recruitment allure.

That doesn’t mean that ISIS won’t continue to be a danger. At Fortune, Simon Mabon points out that it could create more danger in other ways, and that it might end up reinvigorating al-Qaeda:

Following allegations of Baghdadi’s demise, there has been a great deal of infighting among the rank-and-file ISIS members, which suggests that a leadership struggle has begun. Abu Haitham al-Obaidi, a prominent ISIS official in Hawija , has allegedly declared himself caliph. Obaidi has allegedly withdrawn from the group with a large number of followers. One imagines that without a charismatic leader to hold the group together, similar things will continue to happen. Such events will make it much harder for coalition forces to defeat ISIS on the ground.

We must also consider the impact on the group internationally—concerning both those committed to leaving their countries to join the group and those willing to commit violent acts across the West. Ultimately, the ideological message of the group will resonate long after Baghdadi’s death. In Dabiq, the group’s propaganda publication, senior ideologues have referred to a messianic vision of the End of Days, stemming from a war between ISIS and “the armies of Rome,” in a nod to the Crusades. This apocalyptic narrative is imperative in encouraging people to commit acts of terrorism across the world as we have seen in the UK, across Europe, and in the U.S.

Although a huge blow, Baghdadi’s death would feed into this narrative of an existential struggle. His message of certainty that has proved so compelling has certainly been damaged. The number of people joining ISIS from abroad will fall, undoubtedly, but this may result in people committing violent atrocities in their home countries instead. We must not think that this is the end of ISIS. It is perhaps instead the beginning of a different type of threat.

Baghdadi’s death may also serve to invigorate al-Qaeda, who had been marginalized by the emergence of ISIS in 2014. The latter’s combination of a fundamentalist message and the use of extreme violence appealed to many foreign fighters who would previously have traveled to join al-Qaeda. The organization has sought to reinvent itself in the years after ISIS’s emergence, condemning the group’s brutality and the sectarian violence that has become a key aspect of the ISIS agenda. With Baghdadi’s death, al-Qaeda may sense an opportunity to regain ground lost to ISIS in the struggle to be at the vanguard of the global jihadi movement. This could result in a range of attacks as different terrorist groups try to demonstrate their vitality and capabilities.

These possibilities exist, but they have varying degrees of likelihood. The rise of ISIS and its seeming inevitable and irremovable presence in the region was what prompted the rise of affiliates and so-called “lone wolves” in Western nations. Its demise is more likely to discredit their religious claims and produce much less inspiration for such activities.

Their recruitment power was based in large part on the claim that Allah had anointed al-Baghdadi to permanently restore the caliphate. ISIS tried to paper over the fall of the city of Dabiq in its Dabiq propaganda forum, claiming that losing it to another Muslim force didn’t negate their claims of the caliphate fulfilling their end-times prophecy, but the wipeout in Mosul and the coming fall of Raqqa will expose that double-talk as a sham. The recruitment from ISIS propagandists will also falter with the internal war, plus the stories from disillusioned foreign fighters who repent of their decisions … of the few that are left. The threat won’t disappear as the forces splinter and scatter, but it will soon lack enough cohesion to hold territory and use it as bases for further marauding.

The civil war within ISIS is a predictable outcome of the body blows inflicted upon it after the world began taking its threat seriously. No doubt it will return us to the original threat of Islamist terror networks, which by the way have never gone away, so defeating ISIS isn’t the same thing as defeating radical Islamist terror. It does, however, represent a big step in that direction.