-The Awakening Stage (2000-2003), which coincided with the September 11, 2001 attacks, and is described as “Reawakening the nation by dealing a powerful blow to the head of the snake in the U.S.”

-The Eye-Opening Stage (2003-2006), which unfolded after the U.S. invasion of Iraq and was allegedly designed to perpetually engage and enervate the United States and the West in a series of prolonged overseas ventures.

-The Rising Up and Standing on the Feet Stage (2007-2010) involved Al Qaeda’s proactive expansion to new venues of operations, as we have seen in West Africa and the Levant.

-The Recovery Stage (2010-2013), which was originally intended to allow Al Qaeda to consolidate its previous gains and catch its breath, but which ended up having to be adjusted in light of both bin Laden’s killing and the exploitation of new opportunities created by the “Arab Spring” to topple apostate regimes, especially in Syria.

-The Declaration of the Caliphate Stage (2013-2016), when Al Qaeda will achieve its ultimate goal of establishing trans- or supranational Islamic rule over large swaths of territory in the Muslim world. ISIS has clearly stolen a march on Al Qaeda in this respect.

-The Total Confrontation Stage (2016-2020) will occur after the caliphate has been created and an Islamic Army commences the final “fight between the believers and the nonbelievers.”

-The Definitive Victory Stage (2020-2022), when the caliphate will ultimately triumph over the rest of the world.

It is indeed disturbing to map the accuracy of this strategic trajectory dating from 2005 to the present and to realize that, from ISIS’s vantage point, the movement is right on al-Adel’s previously articulated schedule in having declared the caliphate in June 2014. Moreover, no matter how half-baked ISIS’s grandiose pretensions in this respect may be, the fact remains that propaganda doesn’t have to be true: it only has to be believed. For ISIS’s supporters its fulfillment of this seven-stage strategy presents a compelling narrative—thus accounting for ISIS’s continued appeal.

The temptation to dismiss these developments as primarily a “local” phenomenon—confined to the perennially violent, unstable Levant—is further belied both by the growing number of ISIS “provinces,” the recent mid-air destruction of a Russian passenger jet by its Sinai branch, its recruitment of an estimated twenty-five thousand foreign fighters, and its continued efforts to radicalize a worldwide stable of amateurs, whom the group encourages to carry out low-level, lethal attacks in their respective homelands. To date, ISIS has established bases in at least half a dozen countries: stretching from West and North Africa to the Arabian Peninsula and from the Sinai to South Asia and the Caucasus. And, over the past year alone, ISIS-inspired homegrown attacks have occurred in the United States, Australia, Canada, France and Belgium.

The call to violence from ISIS’s chief spokesperson, Abu Muhammad al-Adnani, has proven much more effective in inciting random acts of terror worldwide than more than a decade of similar Al Qaeda entreaties. Absolutely seminal in this respect was al-Adnani’s September 2014 clarion call to would-be ISIS supporters to carry out independent, self-directed acts of violence against ISIS’s enemies in their own countries and homelands.

Some answered al-Adnani’s call in their own countries on their own initiative; others have been explicitly guided by ISIS operatives, either in person or over the Internet and social media. The group thus clearly seeks to inspire individuals to commit acts of terrorism either directly on ISIS’s behalf or in support of ISIS’s ideology and broader political goals.

ISIS, for instance, has claimed responsibility or affiliation with two lone-wolf attacks that took place in Canada in October 2014. The attackers in both incidents had direct contact with ISIS and had sought to leave Canada to become foreign fighters with ISIS in Syria or Iraq before deciding instead to carry out entirely domestic terrorist attacks. ISIS also claimed responsibility for the September 2014 attack in Melbourne, Australia, where a man stabbed two police officers after being summoned for questioning in connection with his public display of an ISIS flag.

In all, the size, weapons and tactics of ISIS forces, combined with their ability to seize and hold terrain and exercise governance (however crude), are probably unique in the annals of terrorism. Accordingly, ISIS (and perhaps also Al Qaeda’s affiliate in Yemen) is now as capable, if not more so, than some of the conventional militaries of established nation-states in the region. Like their government counterparts, this hybrid force holds territory, controls populations, conducts business and enforces laws. ISIS has already defied predictions. It has shown itself to be more brutal, lethal, unconstrained and adaptable than perhaps any substate actor since Cambodia’s Khmer Rouge. In the circumstances, given its barbaric practices, sadistic executions, unmitigated violence and sufficient resources, is it even conceivable that ISIS would display any reluctance to dispatch foreign fighters back to their homelands to undertake future terrorist attacks?

The vast scope of ISIS’s ambitions, the extraordinary number of foreign fighters answering its battle call and the movement’s professed ideology of confrontation with a vast array of foes all but ensures that this struggle will grind on indefinitely. The estimated twenty-five thousand foreign recruits fighting under ISIS’s aegis already exceed by a factor of ten the flow of foreign fighters to Iraq at the height of the war there a decade ago. According to the U.S. House of Representatives Committee on Homeland Security, the number of volunteers for ISIS who have arrived in Syria and Iraq thus far in 2015 was more than three times the number recorded in 2014. Although the majority hails from the Middle East and North Africa (with Tunisia, ironically the only country where the promise of the democratic reforms raised by the Arab Spring appears to have taken root, providing the largest contingent), some 4,500 come from Europe, North America or Australia, including more than 250 Americans. Their ranks include nationals from some eighty countries around the world. Among them was Omar Abdul Azis of Indonesia—the son of Imam Samudra, one of the terrorists convicted of the 2002 Bali bombings.

In just four years ISIS’s international cadre has come to equal even the most extravagant estimate of the number of foreign fighters that the U.S. Intelligence Community believes had traveled to Afghanistan during the 1980s. Viewed from another perspective, more foreign nationals have been trained by ISIS and other radical Islamist groups in Syria than were trained by Al Qaeda in Afghanistan during the five years preceding the 9/11 attacks. The situation in Syria today thus creates the same conditions—but on a far greater magnitude—that led to Al Qaeda’s rise and the attacks on New York and Washington, D.C.

These numbers alone are disturbing. The vast pool of recruits drawn to Syria affords ISIS and any of the other militant Islamist groups active there a surfeit of potential terrorists from which to cherry-pick and potentially dispatch back home to carry out terrorist attacks. As Director Comey noted, Afghanistan in the 1980s and 1990s provides a clear template for this eventuality. The 9/11 Commission Report’s conclusion in this respect is revealing. “Thousands flowed through” bin Laden’s camps before the September 11 attacks, it states, but “no more than a few hundred seem to have become Al Qaeda members.” Indeed, this small number, hand-picked from the larger crop, were subsequently screened, vetted and, having been deemed “worthy,” were provided with specialized terrorist training that enabled them to complete their assigned missions.

In fact, ISIS has long cast a deliberately wide net in its recruiting practices, thus providing it with a larger and more diverse pool of foreign fighters to draw upon and potentially assign to specialized tasks, much like Al Qaeda did in Afghanistan during the years leading to 9/11. ISIS, like the old Al Qaeda, attracts and accepts devout Muslims; but it critically also recruits recent converts, opportunists, profiteers, sadists and thrill seekers—essentially anyone who can contribute to the cause.

In this respect, ISIS’s most fundamental appeal is based on a profound sense of catharsis, empowerment and satisfaction derived from striking a blow at a hated, predatory oppressor. ISIS’s core propaganda messages invoke the same justifications of self-satisfying violence articulated by Frantz Fanon in the 1950s during Algeria’s struggle for national liberation from France. “At the level of individuals,” Fanon famously explained, “violence is a cleansing force. It frees the native from his inferiority complex and from his despair and inaction; it makes him fearless and restores self-respect.”

ISIS effectively propagates this message through the Internet and social media to speak directly to its international audience, thereby preventing the foreign press from misinterpreting or otherwise distorting this basic message. Their grisly propaganda videos of brutal executions, for instance, attract many more viewers than bin Laden and al-Zawahiri’s comparatively staid videos reciting complex theological treatises or imparting didactic philosophical and historical lectures. Through these means the group is able to tailor its messages to specific target audiences. One of ISIS’s most efficacious means of attracting foreign fighters is its visual depictions of heinous acts of violence that not only attract the attention of this audience, but also help motivate and inspire them to join ISIS’s struggle. This also shows why one of the main sources and mechanisms for ISIS recruitment has been prisons, which also serve as training academies and safe locations for indoctrination and planning.