Iraqi federal police officers hold up a captured Islamic State flag in the village of Abu Saif, about four miles from Mosul, on Feb. 22, 2017, in Nineveh province, northern Iraq. (Martyn Aim/Getty Images)

In June 2014, the Islamic State in Iraq and Syria branded itself as a caliphate. Over the past year, its catastrophic loss of population centers and governing infrastructure have prompted an avalanche of analysis on the next phase, projecting the group’s likely reversion to insurgency and terrorism.

But the organizational lens only captures part of the picture. The Islamic State’s success as a protostate and its future as an insurgent/terrorist group was and is fueled by a social movement that ensured a steady flow of adherents to execute its ambitions. Understanding the movement’s appeal is crucial to forecasting its future.

Extremism is built on identity — social parameters that define who is part of the movement and who is excluded, known as “in-groups” and “out-groups.” For extremists, these equate to friends and enemies, the saved few and the damned masses.

Extremist movements are most attractive when the in-group has high levels of “entitativity” or “groupness,” a quality that prompts adherents to perceive a meaningfully real organization.

Decades of research in social psychology show that entitativity has real consequences. Individuals who identify with a well-defined in-group are likely to see the out-group as homogenous, threatening, emotionally driven and irrational. They are also more likely to see current and historical actions by the out-group as “dispositional” rather than situational. Enemies are evil not just because of the context of a conflict, but because of their intrinsic identity.

Extremists define identity using propaganda and ideological texts, which describe the traits, beliefs, history and its practices of both the in-group and out-groups. The Islamic State projected its in-group identity in a barrage of propaganda highlighting the declaration of the caliphate and the institution of governance.

By declaring a caliphate, the group did something that other jihadist groups only talked about, accessing a wellspring of historical, philosophical and theological details. It presented a more sophisticated rejection of the West than other jihadist groups, focused not only on “sinful” cultural elements, but also real, substantial alternatives. And thousands of people from all over the world responded.

Strict, clear and plentiful rules are another quality associated with high entitativity, and the group showcased the idea that Islamic Law, or rather the Islamic State’s interpretation of it, was being implemented in its purest and fullest form.

Other material showed pastoral scenes, a robust bureaucracy and the construction of roads, hospitals and schools. An abundance of identity markers tied it all together, the black flag and other symbols draped over its buildings, currency and memorandums.

Friends and family members of foreign fighters interviewed by researchers at the University of Waterloo were repeatedly told that young people traveled to Syria precisely to live in a more homogenous “Muslim” environment. One young woman from Canada moved to Syria because she felt “dirty and deadly” in her old lifestyle. Dirty because she thought the way of life in Canada was un-Islamic and deadly because she was paying taxes to a government that was bombing “her people.” In Syria, she felt this cognitive dissonance dissipate.

The Islamic State made a repeated and sustained argument that it was about governance, not simply terrorism. Scenes from the living caliphate provided a sense of authenticity and immanence to which few extremist groups could ever aspire, all extensively documented and broadcast to the world over the Internet. Islamic State propaganda provided a flood of Technicolor vignettes featuring its implementation of rules and standards on every aspect of life.

The current Islamic State caliphate — with all of the youth it has galvanized and the media products it has produced — will be repackaged and redeployed for years to come. Yet the loss of the living caliphate is still a devastating blow, in two important senses.

First, the flow of new entitative content has been severely disrupted by the return to an insurgent/covert footing. In August 2015, more than half of all video and photo content put out by the Islamic State was utopian in nature. Typical offerings included images and videos of markets, schools, hospitals, nursing homes and courts — all of the trappings of a highly entitative group, a “real” society, now destroyed by the anti-Islamic State coalition. By September 2017, according to researcher Charlie Winter, only about 10 percent of the organization’s content pertained to its utopian vision, with a sharp drop in total output and a vast increase in the proportion of warfighting content.

Second, the dismantling of social structure is inherently destructive to entitativity. The disruption of the protostate naturally reduces its groupness for potential adherents, because there is no longer a living society to join. While some have written about the appeal of a “virtual caliphate,” there’s no substitute for bricks and mortar. The virtual extension of the Islamic State’s reach served to bolster the reality of its offline analogue. Without the offline component, there is not much to bolster.

In light of the Islamic State’s recent military setbacks, an entire genre of counterterrorism analysis has sprung up around the theme, “the Islamic State is not going away.” This is certainly true, but it’s important not to fall prey to the extremist argument that setbacks simply don’t matter. The loss of the caliphate — and all the traits and qualities that went along with it — will dramatically reduce the Islamic State’s recruiting appeal, unless and until it finds new arguments for entitativity.

Islamic State propagandists and ideologues will shape the next phase. Coalition strikes have eliminated some of its most skilled ideological constructors — including Abu Muhammad al-Adnani and Turki al-Binali. Their successors may or may not be as adept at their craft, but they will almost certainly lack the raw materials that propped up the organization’s previous “groupness.”

As the Islamic State evolves, we should not only remind people about its ongoing threat. We should also acknowledge and highlight the fact it has suffered enormous losses that will cripple the effectiveness of its previous approach to recruitment. As its slogan famously states, the Islamic State will likely “remain,” but it has lost far more than territory. It has lost the living, beating heart of its appeal.

J.M. Berger is a fellow with the International Centre for Counter-Terrorism — The Hague. He is currently working on his third book, The Elements of Extremism (MIT Press, 2018).

Amarnath Amarasingam is a senior research fellow at the Institute for Strategic Dialogue and a postdoctoral fellow at the University of Waterloo, where he co-directs a study of Western foreign fighters.