ISIS Terrorism: History, Tactics, and Global Legal Status Explained

Table of Contents#

Origins and Evolution of ISIS: From Insurgency to Caliphate 1.1 Roots in Post-Invasion Iraq 1.2 Split from Al-Qaeda and Rise to Dominance 1.3 Decline of Territorial Control
Tactical Strategies of ISIS: Fear, Propaganda, and Asymmetric Warfare 2.1 Asymmetric and Guerrilla Tactics 2.2 Propaganda and Digital Recruitment 2.3 Brutality as a Tool of Control 2.4 Cyberterrorism and Online Operations
Legal Status of ISIS: Designation and Accountability 3.1 Global Terrorist Designations 3.2 International Legal Frameworks 3.3 Prosecuting ISIS Members: Challenges and Progress
Conclusion
References

1. Origins and Evolution of ISIS: From Insurgency to Caliphate#

ISIS’s story is deeply intertwined with geopolitical instability, extremist ideology, and power vacuums created by regional conflicts.

1.1 Roots in Post-Invasion Iraq#

In 2004, Jordanian militant Abu Musab al-Zarqawi founded Jama’at al-Tawhid wal-Jihad (JTJ), a Sunni extremist group focused on attacking U.S. forces and Shia civilians in Iraq. The group later pledged allegiance to al-Qaeda, rebranding as al-Qaeda in Iraq (AQI). Following Zarqawi’s death in a 2006 U.S. airstrike, AQI merged with other insurgent groups to form the Islamic State of Iraq (ISI), led by Abu Omar al-Baghdadi.

By 2010, ISI was weakened by U.S. counterinsurgency operations, but the 2011 Syrian civil war provided a new lifeline. Abu Bakr al-Baghdadi, who took over ISI that year, sent fighters to Syria to join the insurgency against President Bashar al-Assad. This faction became known as the Islamic State of Iraq and al-Sham (ISIS), marking the group’s expansion beyond Iraq’s borders.

1.2 Split from Al-Qaeda and Rise to Dominance#

Tensions between ISIS and al-Qaeda grew as ISIS refused to follow al-Qaeda’s orders to limit its operations in Syria. In 2013, al-Qaeda leader Ayman al-Zawahiri formally disavowed ISIS, declaring it a rogue organization. Undeterred, ISIS continued its expansion, capturing key cities in Iraq and Syria.

In June 2014, ISIS seized Mosul, Iraq’s second-largest city, and declared a global caliphate, renaming itself the Islamic State (IS). Abu Bakr al-Baghdadi was named caliph, claiming authority over all Muslims worldwide. At its peak in 2015, ISIS controlled approximately 88,000 square kilometers of territory across Iraq and Syria, with an estimated 30,000 to 40,000 fighters, including thousands of foreign volunteers from over 100 countries.

1.3 Decline of Territorial Control#

A coalition of international forces, including the U.S., UK, France, and local partners like the Kurdish Peshmerga and Syrian Democratic Forces (SDF), launched a massive military campaign to defeat ISIS. By 2017, ISIS had lost major strongholds like Raqqa (its Syrian capital) and Mosul. In March 2019, the SDF captured the last remaining ISIS-held territory in Baghuz, Syria, effectively ending the group’s territorial caliphate.

However, ISIS did not disappear. It reverted to an insurgency, carrying out sporadic attacks in Iraq, Syria, and other regions like Afghanistan, Africa, and Southeast Asia. As of 2024, the group remains a persistent threat, with an estimated 10,000 to 15,000 fighters in Iraq and Syria alone.

2. Tactical Strategies of ISIS: Fear, Propaganda, and Asymmetric Warfare#

ISIS’s success in gaining territory and recruits was driven by a combination of innovative tactics, psychological warfare, and effective use of digital technology.

2.1 Asymmetric and Guerrilla Tactics#

ISIS relied heavily on asymmetric warfare to counter better-equipped coalition forces. Key tactics included:

Suicide Bombings: The group carried out hundreds of suicide attacks using explosive vests, vehicle-borne improvised explosive devices (VBIEDs), and drones. These attacks targeted military bases, civilian crowds, and infrastructure to inflict maximum casualties and instill fear.
Hit-and-Run Attacks: Small teams of ISIS fighters would launch quick strikes against security forces before retreating to rural or urban hideouts, making it difficult for coalition forces to track them.
Tunnel Networks: In cities like Mosul and Raqqa, ISIS built extensive tunnel systems to move fighters, store weapons, and avoid airstrikes. These tunnels also served as command centers and prison facilities.

2.2 Propaganda and Digital Recruitment#

ISIS was a pioneer in using social media and digital platforms to spread its ideology and recruit fighters. Its propaganda machine produced slick, high-quality videos showing executions, military victories, and life under the caliphate. These videos were shared across platforms like Twitter, Telegram, YouTube, and Facebook, reaching a global audience.

The group targeted vulnerable individuals, including disaffected youth in Western countries, by offering a sense of purpose and belonging. It used encrypted messaging apps to communicate with recruits, guiding them to travel to Syria/Iraq or carry out “lone wolf” attacks in their home countries. For example, the 2015 Paris attacks, which killed 130 people, were carried out by ISIS-inspired fighters.

2.3 Brutality as a Tool of Control#

ISIS used extreme violence to maintain control over territories and deter opposition. Public executions, beheadings, crucifixions, and stonings were regularly filmed and shared online to intimidate civilians and enemies. The group also targeted ethnic and religious minorities, including Yazidis, Christians, and Shia Muslims. In 2014, ISIS captured the Yazidi homeland in Sinjar, Iraq, killing thousands of men and enslaving an estimated 7,000 women and girls – a crime later classified as genocide by the UN.

2.4 Cyberterrorism and Online Operations#

ISIS expanded its operations into cyberspace, using technology to support its goals:

Hacking: The group’s cyber wing, known as the Islamic State Hacking Division (ISHD), carried out attacks on government websites, media outlets, and social media accounts of military personnel.
Ransomware: ISIS affiliates used ransomware to extort money from individuals and organizations, generating funds for their operations.
Online Fundraising: The group raised millions of dollars through crowdfunding platforms, cryptocurrency, and illegal trade (like oil smuggling and human trafficking).

3. Legal Status of ISIS: Designation and Accountability#

ISIS’s actions have been widely condemned by the international community, which has taken steps to legally designate the group as a terrorist organization and hold its members accountable for crimes against humanity.

3.1 Global Terrorist Designations#

ISIS is listed as a terrorist organization by most countries and international bodies, including:

United Nations: The UN Security Council added ISIS to its list of terrorist groups in 2014 (Resolution 2170), requiring member states to freeze the group’s assets, ban travel of its members, and prevent the supply of weapons.
European Union: The EU designated ISIS as a terrorist organization in 2014, imposing sanctions such as asset freezes and travel bans.
United States: The U.S. classified ISIS as a Foreign Terrorist Organization (FTO) in 2014, enabling the government to prosecute individuals who support or join the group.
Other Countries: Australia, Canada, India, and the UK are among the many nations that have formally designated ISIS as a terrorist organization.

3.2 International Legal Frameworks#

Several international legal instruments apply to ISIS’s crimes:

International Humanitarian Law (IHL): Also known as the Geneva Conventions, IHL prohibits acts like genocide, war crimes, and crimes against humanity. ISIS’s actions, including the enslavement of Yazidis and targeted killings of civilians, violate these conventions.
UN Counter-Terrorism Treaties: Treaties like the International Convention for the Suppression of the Financing of Terrorism (1999) and the International Convention Against the Taking of Hostages (1979) provide a legal basis for prosecuting ISIS members involved in financing terrorism and hostage-taking.
International Criminal Court (ICC): The ICC does not have inherent jurisdiction over crimes committed in Iraq or Syria, as neither country is a party to the Rome Statute. The ICC can only investigate and prosecute such crimes if the UN Security Council refers the situation or if the country in question accepts the Court's jurisdiction. So far, the Security Council has not referred the Syrian situation to the ICC. The ICC has been able to investigate ISIS crimes only based on the UN Security Council's Resolution 2170 (2014), which called for accountability for ISIS's actions. In 2021, the ICC issued arrest warrants for two ISIS members accused of genocide against Yazidis.

3.3 Prosecuting ISIS Members: Challenges and Progress#

Bringing ISIS members to justice is a complex process due to several challenges:

Jurisdiction: Many ISIS members are foreign fighters, making it difficult to determine which country has the right to prosecute them. Some countries have repatriated their citizens to face trial, while others have chosen to leave them in detention camps in Syria and Iraq.
Evidence Collection: Gathering evidence of ISIS crimes is challenging, as many crime scenes were destroyed during military operations, and witnesses may be reluctant to testify due to fear of retaliation.
Detention Camps: Thousands of ISIS fighters and their families are held in overcrowded detention camps in Syria (like Al-Hol) and Iraq. These camps pose a security risk and raise questions about how to handle detainees long-term.

Despite these challenges, progress has been made:

National Trials: Countries like Germany, France, and the UK have prosecuted hundreds of returning ISIS members on charges of terrorism, murder, and war crimes. For example, in 2020, a German court sentenced an ISIS member to life in prison for his role in the enslavement of Yazidi women.
Iraqi Courts: Iraq has tried thousands of ISIS members, including foreign fighters, under its counter-terrorism laws. However, concerns have been raised about due process and fair trials in some cases.
Yazidi Justice: In 2022, the first-ever trial for ISIS crimes against Yazidis was held in Germany, using universal jurisdiction to prosecute a former ISIS member for genocide, crimes against humanity, and war crimes.

4. Conclusion#

ISIS’s rise and fall highlight the complex interplay between political instability, extremist ideology, and technological innovation. While the group no longer controls territory, it remains a persistent threat through insurgent attacks and online propaganda. Understanding its history, tactics, and legal status is critical for developing effective counter-terrorism strategies, ensuring accountability for its crimes, and preventing the rise of similar extremist groups in the future. The international community must continue to collaborate on intelligence sharing, legal prosecution, and addressing the root causes of extremism to mitigate the ongoing risks posed by ISIS and its affiliates.

5. References#

United Nations Security Council. (2014). Resolution 2170. Retrieved from https://www.un.org/en/sc/meetings/docs/2014/sc11591.doc.htm
United Nations Security Council. (2014). Resolution 2199. Retrieved from https://www.un.org/en/sc/meetings/docs/2014/sc11640.doc.htm
International Criminal Court. (2021). ICC Issues Arrest Warrants for Two Islamic State Members for Crimes Against Yazidis. Retrieved from https://www.icc-cpi.int/news/icc-issues-arrest-warrants-two-islamic-state-members-crimes-against-yazidis
Council on Foreign Relations. (2024). Islamic State (ISIS). Retrieved from https://www.cfr.org/backgrounder/islamic-state-isis
BBC News. (2019). Syria’s Baghuz: Last ISIS stronghold falls to SDF. Retrieved from https://www.bbc.com/news/world-middle-east-47562532
Human Rights Watch. (2015). Islamic State’s Systematic Enslavement of Yazidi Women and Girls. Retrieved from https://www.hrw.org/report/2015/09/02/they-came-to-kill/islamic-states-systematic-enslavement-yazidi-women-and-girls