18.14 ISIS (2013)

ISIS emerged in its modern form in 2013, but its roots go back to the Iraq War (2003-2011) and the earlier group Al-Qaeda in Iraq (AQI). After the U.S. invasion of Iraq in 2003, Abu Musab al-Zarqawi built a brutal Sunni militant network that later aligned with Al-Qaeda. After Zarqawi’s death in 2006, the group evolved into the Islamic State of Iraq, and by 2013 it had expanded into Syria and became known as the Islamic State in Iraq and al-Sham, or ISIS.

The group is also often called ISIL, referring to the Islamic State in Iraq and the Levant. Another widely used term is Daesh, based on the group’s Arabic name. Many governments, journalists, and people in the Middle East have preferred the term Daesh because it denies the group the legitimacy it sought through the name “Islamic State.”

ISIS pushed the jihadist model further than almost any earlier Islamist extremist group. It combined territorial conquest, mass-casualty terrorism, state-building, online propaganda, apocalyptic ideology, and a self-declared caliphate into one movement. Unlike Al-Qaeda, which initially operated more as a flexible transnational network, ISIS sought to conquer and govern territory directly while also inspiring or directing attacks far beyond its borders.

A major turning point came in June 2014, when ISIS captured Mosul, Iraq’s second-largest city. Soon afterward, on June 29, 2014, ISIS declared a caliphate and named its leader, Abu Bakr al-Baghdadi, as caliph. By doing this, ISIS claimed that it was no longer simply a terrorist organization or insurgency, but the legitimate global Islamic state for all Muslims under the rule of a successor to Muhammad in political leadership.

———

Their declaration of statehood helped ISIS attract recruits from around the world. Thousands of foreign fighters traveled to join the group, drawn by ideology, propaganda, a sense of purpose, or the belief that they were participating in end-times and the rebirth of a powerful Islamic order.

ISIS uses professional media production, social media, and highly publicized violence to spread fear, build prestige, and recruit internationally. They use high-definition cameras and professional editing to create cinematic propaganda that appeal to young people globally. This digital strategy has helped attract an estimated 25,000 foreign fighters from over 100 different countries.

ISIS also engages in what experts call performative destruction—carefully staged, high-quality videos showing the demolition of historic sites to spread propaganda and erase the past. The group has destroyed or damaged over 150 sites, including the ancient city of Palmyra, the Tomb of Jonah, and the Great Mosque of al-Nuri in Mosul. Fighters used sledgehammers and drills to smash priceless statues at the Mosul Museum. They claimed these artifacts were idolatrous, while frequently looting smaller, portable items to sell on the black market to fund their operations.

Additionally, ISIS established a comprehensive educational system to spread its ideology among children and teenagers. Children were trained as fighters, spies, and even executioners to ensure the group’s transgenerational survival.

———

Part of ISIS’s appeal came from its apocalyptic ideology.

The group did not present itself as just another militant organization fighting for land or political power. It claimed to be living in the final struggles before the end times, drawing on selective interpretations of Islamic prophetic traditions to frame its battles as part of a cosmic war between true believers and their enemies. This gave its violence a grand, urgent, and highly theatrical quality. Followers were not simply being asked to join an insurgency; they were being told they were participating in sacred end-time history.

ISIS also used sectarian violence strategically. It did not merely hate Shia Muslims, Yazidis, and other targeted communities on an ideological level; it also understood that spectacular violence could deepen social divisions and make coexistence harder. Like Zarqawi before it, ISIS deliberately attacked Shia civilians, shrines, and communities in order to provoke retaliation, inflame sectarian war, and force Sunnis to choose sides. In this way, sectarian brutality was not only an expression of belief — it was also a calculated strategy for polarization and recruitment.

ISIS has become notorious for extreme brutality. It has carried out mass executions, beheadings, sexual slavery, forced displacement, hostage-taking, and attacks on civilians, while imposing a harsh and violent interpretation of Islamic law in the areas it controlled. Its rule in cities such as Mosul and Raqqa became one of the clearest modern examples of how an extremist movement could combine terrorism with territorial governance.

At the same time, ISIS did not survive on ideology alone. It built a self-sustaining war economy that helped it function more like a state than a typical insurgent group.

At its peak, ISIS was considered the wealthiest terrorist organization in history. At different points, ISIS drew revenue from oil smuggling, extortion, taxation, looting, kidnappings for ransom, confiscation of property, and control of trade routes. This gave the group a level of financial independence that made it unusually resilient and allowed it to pay fighters, govern territory, and sustain military operations.

———

ISIS grew out of Al-Qaeda in Iraq, but differs from Al-Qaeda in important ways. Both were Sunni jihadist movements, but ISIS was even more extreme in its willingness to declare other Muslims apostates, slaughter civilians on a large scale, and immediately claim statehood through a caliphate. Its brutality was so extreme that Al-Qaeda publicly broke with it, and the two groups became bitter rivals.

Although ISIS lost most of its territorial “caliphate” after sustained military campaigns in Iraq and Syria, it continued to inspire attacks, attract affiliates, and compete with Al-Qaeda in different regions. Even after its territorial losses, ISIS remained one of the most influential extremist organizations of the modern era because it reshaped how jihadist movements used propaganda, global recruitment, sectarian war, and symbolic claims to statehood.

ISIS represents an extreme culmination of many trends we have already traced: the post-Iraq War insurgency, the global jihadist model of Al-Qaeda, the use of sectarian violence, the seizure of territory, the creation of a war economy, and the attempt to build a state under an extremist interpretation of Islam. In that sense, ISIS was the product of earlier wars, networks, and ideological developments — but it pushed them to a new level of brutality and ambition.

ISIS is the last Islamic extremist group that we will look at in this module, there are, however, more groups that exist which we have not touched on.

In section 18.15, we will conclude Module 18 with an overview of Islamic Extremism.